Stage 4 is currently in the works but will add a Supersprint tubular header and improve the location of the cats. At the back of the exhaust, a stainless Supersprint muffler system was installed to tune the engine note, which allows the engine to sing without the boy-racer whine of a less-sophisticated system.
Dressing up
Turner Motorsport decided to dress its white stage 3 E90 in designer duds from Hartge. As you can see, a front chin spoiler and 19" Classic II wheels took care of the exterior. The changes are dramatic and make a stock E90 look ho-hum in comparison. Every E90 should look this good.
The wheels are 19x8" in front and 19x9" out back, with broad 265/30 tires putting power to the pavement.
Adding to the aggressive stance is a set of H&R Street coilovers. Originally designed for racecars, H&R has engineered these for daily driving with spring rates and shocks tuned for the road. The coilovers are super-low, so if you're only interested in a slight drop, look for H&R Sport springs. The company's sway bars further reduce body roll and understeer.
While the suspension and tires work to increase physical grip, a limited-slip differential puts all the engine's power to the ground. The factory LSD has been sorely missed in recent years as BMW now relies on traction control to rein in power, which also reins in the fun. With a TMS limited-slip putting power to both rear wheels, the traction control can be switched off without sacrificing grip.
Wrapping up
The upgrades to the E90 325i/330i add to a capable and rounded performer. With good looks and speed to match, not much is forgotten. In fact, only BMW's 300hp 335i twin-turbo surpasses the TMS E90 in power, but maybe not in fun.
The 325i modifications give it much more intensity, and more for the driver to enjoy. It invites you to push harder on the throttle until you run out of gears. It has the spirit of the dynamic '95 M3 and no longer feels like BMW's entry-level car.
It's going to cost you under $5k to get your 325i up to 330i territory, so you can really enjoy owning one of BMW's finest sports sedans.
TMS Background
The guys at Turner Motorsport (TMS) in Massachusetts have been around longer than the trees - they've been tuning BMWs since '89. The company was originally started to support Will Turner's racing ambitions and now translates its racing expertise and hardware into products for everything from daily-driven street cars to radical racing machines.
We worked with them on our Project 330i (et 6/05) and discovered they magnified the classic BMW attributes without sacrificing much more than comfort- we went for a full Grand Am track setup and it was a little stiff...
With so much experience working and racing only BMWs, it's no surprise they've been extremely successful. Back in '03 and '04 they won the Speed World Challenge Touring Car series. And last year TMS was the only professional BMW team to win any US races, sewing up four championships - for GS and ST drivers and team - in the Grand Am Cup endurance series (www.turnermotorsport.com).