As if building yourself an E46 M3 Sedan wasn’t already impressive enough, this awesome modified BMW is packing over 500whp, and it’s simply awesome on every level.
When it comes to the M3, BMW has been rather indecisive about what body styles can wear the badge. The first-gen car was available in two-door and convertible forms before BMW added a four-door saloon for the E36, and then cruelly took it away when the E46 M3 launched, finally deciding it deserved to be part of the family once the E9x range was introduced. This means that if you happen to be an E46 M3 fan, like most of you reading this will be, and you want more doors, you are straight out of luck. That is, of course, unless you decide to do something about it yourself…
Shawn’s BMW collection
Most of the time, you will find Shawn Robertson busy doing software development, but when he’s not doing that, you will find him driving one of his three BMs. This is a collection, which, alongside this modified BMW E46 M3 sedan, features an Imola red X5 4.8iS, which serves as his daily driver (respect), and an Orient blue E46 Touring, a project car he recently picked up, and is planning on working on with his son, currently eight.
Shawn grew up around American cars but initially took to Japanese machinery in the early 2000s, Hondas in particular, building himself a 450whp turbo 1993 hatchback in 2005, so he’s clearly no stranger to the pleasure of forced induction.
From JDM to BMW
Shawn’s switch from JDM to German power came about when he sold his third-gen RX-7 for a 1998 E36 M3 Sedan; after this was sadly T-boned, he moved into an Avus blue E36 M3 Coupé, and since then, his passion for BMWs has only grown stronger. But while Shawn may have dabbled with turbo power in the past with his modded Honda, this E46 project was something on an entirely different scale altogether.
“I divorced back in 2016, and, for that marriage, I was not into cars at all with no time and had sold everything,” explains Shawn. “I needed an outlet to deal and cope with the recent divorce. A buddy of mine sent me a link to an Imola red ZHP and said I should get it. I searched around on ZHPMafia forums and found a dealer in Miami that specifically sold ZHPs at the time and ended up scoring mine with 165k miles for $7500.” Seven years later, it’s clear that this was the right car for Shawn and the one he needed in his life at that time.
Plans for the BMW E46 M3
You will notice that Shawn has made no mention of his intentions to create a four-door modified BMW E46 M3 sedan, and that’s because, when he bought this, he had no plans in mind for it. “I mainly wanted to get back into a BMW and a manual transmission to have some fun with it.
Of course, as things go, in typical fashion, you start searching forums, websites, Facebook groups etc. and see all of the potential available, and so the story goes,” chuckles Shawn. “The very first mods done to the car were projector light retrofits as the E46 Sedan facelift cars were notorious for melted/burned projector bowls. After that, small cosmetic changes such as M3 mirror retrofits, interior changes etc.,” he says, but very quickly, the mods began to snowball and the build that you see before you began to take shape.
Turbocharging the S54 engine
While there is a lot to enjoy on this modified BMW E46 M3 sedan project, undoubtedly the most exciting part is what you will find under the bonnet. “Surprisingly, the engine itself is a stock, unopened 144k-mile S54B32,” Shawn begins. “It has had the rod bearing service competed with OEM WPC treated bearings 16k miles ago, but, other than that, it is bone stock internally. In 2016, I had an amazing local BMW performance shop, Lins Specialty Automotive perform the engine swap and couldn’t be happier,” Shawn enthuses.
“I have built a custom turbo kit with a ton of help from other forced induction friends, as well as tons of information and knowledge on forums. Previously, I had a carbon airbox installed, and though it sounded beautiful, the car was terribly slow, and I just couldn’t stand it: all that beautiful induction noise, but the car wasn’t really moving anywhere compared to today’s cars,” he laments. “I really wanted a setup that could give me the power of today’s M cars but still have streetability and not sound like a race car on the streets either,” he explains, and that’s exactly what this custom turbo setup has delivered.
Engine modifications on the BMW E46 M3 sedan
Shawn has put together the entire kit, and he’s cherry-picked the perfect parts to suit his needs and the car. There’s a SPA T4 turbo manifold accommodating a BorgWarner S366 SXE 1.0 A/R turbo, connected up to a 3” catless downpipe. A 3” intercooler has also been added, along with a Tial 50mm BOV and 44mm wastegate, plus a custom aluminum S54 Intake manifold. The custom wastegate routes back into the exhaust system, ideal for keeping things on the quieter side, and the exhaust system is comprised of a Status Gruppe 3” second section and Eisenmann Sport silencer. The S54 mates to a Getrag 420G six-speed gearbox from an E46 M3, with a DKM twin-disc clutch system, with power put to the road via an M3 3.62 LSD.
And power is one thing this build is not short of, with the turbo S54 developing 530whp (that’s around 610 at the flywheel) and 430lb ft wtq, but it’s doing that without even breaking a sweat. “That’s at a modest 11.5 psi on E85 with the stock engine computer – I didn’t go for a standalone EMS, so the car passes all emission tests and is street legal in all the states,” explains Shawn, which makes this build all the more impressive.
Modified BMW E46 M3 sedan transmission upgrades
If that was the end of this E46, we’d still consider it to be absolutely epic, but Shawn has really put in the work to make this a complete build, and the styling is a big part of that. “After I swapped in the S54 engine and transmission, I drove the car like this for about a year. Then I searched E46 M3 Sedan and came across other conversions online by JeppeJ on e46fanatics,” Shawn tells us. “I was blown away by the attention to detail, and I wanted to attempt the same with my car. I started ordering parts, mocking up pictures in Photoshop and then started selling parts off my car to really seal the decision.
Exterior modifications
“I went to a junkyard and cut out M3 rear quarter panels and rear trunk floors, ordered a set of M3 Sedan fenders from 2M Autowerks and fitted them along with an M3 hood, bumper and headlights. Once I fitted exterior parts as much as I could, I dropped the car off at Superstar Customs in Lilburn, GA for the rear quarter panel/door work,” Shawn says.
“Once completed, I had a local, talented painter, Tony, with Born2Doit Customs, who repainted the entire car in a three-stage paint job in the factory Imola red 405/2. I performed the carbon fiber roof conversion myself with the help of local friends and another great local business, DNA Auto Glass which did a wonderful job removing my front and rear screens in perfect condition and reinstalling them as well.
“A friend named Ronald Kamphuis, who actually was visiting from Holland at the time, performed the trunk floor swap, and when I say this guy is a metal magician, it would be an understatement,” laughs Shawn. All of that gives you an idea of the scale of the work involved in turning this E46 into a full-on M3 replica. The result is simply flawless, and this build looks like it could have come from the factory in four-door form.
Modified BMW E46 M3 sedan chassis and wheels
Drinking in those seductive M3 sedan lines, you realize that away from the wild under-bonnet enhancements, Shawn’s approach for the rest of the car was very much an OEM one, and so when it came to wheels, something wild simply wouldn’t suit. “I wanted the best-looking E46 OEM wheel I could find that fit the theme of the car,” says Shawn. “That turned out to be 19” Style 163M wheels, I love the concavity of the rear wheels and the staggered fitment,” and they’re definitely a winner in our books. The Style 163s suit the modified E46 Sedan shape so well, they fill the arches perfectly, and they just look so good, especially paired with the drop that this 3 Series has been enhanced with.
Suspension
“I am still rocking the E46 M3 DGR coilover suspension I installed 16,000 miles ago,” says Shawn of his setup. “Honestly, I had spent so much money on the car and the S54 swap at the time that I was looking to save money where I could, but the DGR coilovers at $800 turned out to be a fantastic bang for the buck, and they ride great!” he enthuses. But there’s a lot more going on beneath the surface than just coilovers.
Check out the tech spec, and you’ll see that AKG features heavily in the chassis upgrades, with the company’s poly bushes fitted throughout, and then you’ve got the M Performance carbon fiber strut brace under the bonnet and Turner Motorsport front and rear adjustable anti-roll bars. Shawn has also added E46 M3 lower front control arms and rear trailing arms, as well as an E46 M3 CSL blue tag quick-ratio steering rack and CSL MK60 ABS/DSC Motorsport system. All of this means this E46 M3 sedan build has a chassis that allows Shawn to really make the most of all that power and really enjoy driving his magnificent creation. The brakes, meanwhile, are Porsche 996 911 calipers front and rear equipped with CSL rotors and braided brake lines, and this combo offers serious stopping power.
E46 M3 sedan interior upgrades
Finally, we come to the interior of the modified E46, and Shawn had a clear idea of what he wanted. “The interior has been changed so many times, but for this final form, I really wanted something as close to OE spec as possible,” he says. “One of the rarer-spec M3 interiors was the M Texture F2AT interior, and it was only available on M3 Coupés, as well as non-M Clubsport coupés, but, sadly, no sedans. The closest sedans got was the Full Cloth Alcantara interior, which is beautiful, and I had it as well, but it wasn’t M3, and I needed an M3 interior,” he reasons.
“I sourced the reproduction F2AT material from ASCFabrics and sourced two sets of M3 seats, one leather with heating and then another with manual seat bases. Master Smart Repair in North Carolina created the beautiful leather/Alcantara seat covers front and rear, and they were able to integrate the rear M arch into the rear seat backs, something sedans never got. I performed the door cards myself, as well as the Alcantara suede slicktop headliner re-cover,” he says, and all that work has created a gloriously OEM-looking interior that really fits this build perfectly. The seats and door cards look fantastic, and we can see why Shawn was so keen on getting his hands on this pattern, and then you’ve got the extra touches like the M3 CSL steering wheel, the M3 gauges, and even the M3 boot liner, and we love all of it.
Conclusion
Needless to say, we love the whole build, too. Six years of hard work have paid off in a big way, and this modified E46 is a simply magnificent project. Shawn has really gone the extra mile to make it extra special, and to say he’s satisfied would be an understatement, and with a build of this caliber, picking just one standout modification proves impossible.
“That’s an extremely tough one,” he chuckles. “I can’t make a single standout choice, honestly. I feel the car is a culmination of hard work all-round, and to choose any specific feature as a favorite would do a disservice to anything else not chosen,” he says, and we totally get that. And, unlike so many feature cars, this one feels truly complete. “I feel like the car is done from a project standpoint and ready to be enjoyed for years to come,” enthuses Shawn. That’s what it’s all about, enjoying the car you’ve spent years building, and with a car like this, enjoyment comes very easily.
Tech Spec: Modified BMW E46 M3 Sedan
Engine:
3.2-litre straight-six S54B32; OEM BMW WPC-treated rod bearings; SPA T4 turbo manifold; BorgWarner S366 SXE 1.0 A/R turbo; 3” cat-less downpipe; 3” intercooler; 3” cold-side piping; 2.5” hot-side piping; 4” turbo cold air intake behind passenger side fog light; Tial 50mm BOV and 44mm wastegate; custom aluminum S54 intake manifold; all stainless steel black PTFE oil lines and AN fittings; custom wastegate; 3” downpipe; Status Gruppe 3” section 2; Eisenmann Sport rear silencer; custom oil scavenge pump solution; Innovate LC-2 wideband sensor and controller; Tuned by Hassan @ HTE Performance.
Power and torque:
530whp and 430lb ft wtq @ 11.5 psi.
Transmission:
Getrag 420G six-speed manual gearbox; DKM Twin-Disc Clutch system; M3 3.62 differential with LSD.
Chassis:
8×19” (front) and 9.5×19” (rear) Style 163M wheels with 225/35 (front) and 255/30 (rear) Continental Extreme tires; DGR coilovers with adjustable shocks and adjustable camber/caster mounting plates; BMW M Performance Carbon Fiber Strut Brace; E46 M3 lower front control arms; E46 M3 rear trailing arms; SPC adjustable rear control arms for camber; AKG Rear Subframe Reinforcement Plate Kit; poly front control arm bush set and differential mount bush set; aluminum rear trailing arm bushes; poly rear subframe bush set and spherical RTAB; front control arm bushes and engine mounts; Turner Motorsport front and rear anti-roll bars; CSL blue tag quick-ratio steering rack; CSL MK60 ABS/DSC Motorsport system; Porsche Brembo 996 911 calipers with CSL rotors and stainless steel lines (front and rear).
Exterior:
Full respray in Imola red 405/2; custom front M3 Saloon front arches; OEM M3 bonnet; OEM M3 Euro front bumper with carbon-Kevlar reinforcement bar; G5-BRT OEM M3 bi-xenon headlight retrofit; European infrared Climate Comfort windscreen; 2M Autowerks custom 1×1 weave carbon fiber roof; OEM M3 side skirts; cut-out and weld-in M3 rear quarter panels; cut-out and weld-in M3 rear boot floor to run a full M3 exhaust; weld-in proper mounting points for M3 lower underside V-brace; OEM M3 rear bumper with carbon-Kevlar reinforcement bar; Seibon CSL boot lid.
Interior:
Complete interior refinished in OEM BMW Anthracite M Texture Alcantara and black Nappa leather F2AT; E46 M3 front seats on manual seat bases with custom-retrofitted width adjustable side bolster and lumbar system; rear saloon seats custom reupholstered to match OEM M3 rear seats with integrated arches and M texture cloth; door panels reupholstered in F2AT M texture cloth; Alcantara slicktop (non-sunroof) suede headlining; M3 CSL Alcantara steering wheel with functional M track mode button.
OEM M3 illuminated gear knob and leather gaiter with Alcantara handbrake gaiter; custom OLED display integrated into M3 cluster in former SMG LCD section with boost and AFR display; custom GFB G-Force III electronic boost controller mounted in dashboard center vent; rare/Euro-only/retrofitted parts including electric rear sunshade; rear door sun shades; BMW 2kg halon fire extinguisher (no USA cars came with this); warning triangle and first aid kit (no USA cars came with this); electric folding mirrors (no USA cars came with this); PDC; auto-dimming heated side mirror glass (E90 retrofit); TPMS; retractable headlight washers.
Thanks to Total BMW. Photos: Mitchell Dolan, Halston Pitman.
