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The E82 BMW 135i Coupe is a future classic—compact, turbocharged, and ripe for transformation. This particular N54-powered example came into the Xatrix workshop a little tired, leaking from multiple places and misfiring intermittently. Driven by a defined goal and Xatrix’s recommendations tailored to both budget and performance, the owner curated a focused upgrade list that breathed new life into the car.
What followed was a mini restoration with some tasteful mods applied (were it 15 years older we’d be calling it a restomod!), improving reliability, handling, and power delivery with carefully chosen parts and a dyno-proven tune ready for the track. Here's what went into turning this worn-out 135i into a proper performance weapon.
Old suspension was, well exactly that. Old and tired. Why fix when you can upgrade?
The car ended up with a combination of Bilstein dampers and Eibach lowering springs. This suspension setup not only tightens up the ride and improves responsiveness but also lowers the car by up to 40mm, giving it a more aggressive, planted look.
It’s a balanced upgrade for street and occasional track use—delivering improved body control without sacrificing ride quality. Perfect for daily-driven performance builds.
The biggest flaw of the 135i (or any 35i BMW for that matter, is omission of an LSD in stock from, throw any downpipe and tune on your N54, but as long as you are running an open diff, all you will get for your efforts is 1-tire fire and slow corner exits.
Thus, a helical limited-slip differential from MFactory was also installed during the rebuild—giving the car vastly improved traction and power delivery, especially when cornering or accelerating out of tight turns. While this particular unit isn’t sold via ML Performance, it’s a standout addition for anyone serious about making the most of their N54’s capabilities.
To improve drivetrain stability and reduce unwanted movement under load, the rear subframe was removed and fitted with solid aluminium rear bushings from Millway Motorsport. These bushings drastically reduce flex, tightening up the rear end for more predictable handling and better power transfer—especially when combined with the upgraded differential.
The increased rigidity does translate to slightly more road feedback, but for performance-minded builds, it's a worthwhile trade-off.
only improve safety but also inspire greater confidence behind the wheel.
Braking performance is just as important as power, especially in a build like this. The factory brakes showed signs of wear, including warping and cracking—so they were replaced with EBC performance discs and Yellowstuff pads, chosen for their versatility and reliability.
This setup offers improved stopping power, better heat dissipation, and greater resistance to fade under spirited driving. We opted for EBC Yellowstuff pads specifically because they strike an ideal balance between street comfort and track-ready performance, making them a perfect fit for a tuned daily driver that’s occasionally pushed hard. These upgrades not only improve safety but also inspire greater confidence behind the wheel.
With the chassis and handling fixed it was time to jump onto our next quest:
POOOOOOOOOOOOOOOOOOOOWWWWEEEEEER
One of the first major upgrades was the installation of a Masata intake pipe—a high-flow replacement for the restrictive factory piping. On N54 engines, the OEM intake setup is known to be a bottleneck when you are chasing more power, aaand they look a lot better than drab 10 year old plastics.
The Masata pipe improves airflow into the turbo by reducing turbulence and pressure drop, helping the turbo spool quicker and breathe more freely under load. It also eliminates the common failure points in the OEM plastic system, making it both a performance and reliability upgrade. The design fits snugly within the tight engine bay, maintaining OEM+ aesthetics while offering a measurable improvement in response.
With increased power comes increased heat—as the factory intercooler struggles to cope, intake air temperatures (IAT’s) raise and power drops. The Masata intercooler was fitted to combat this.
Thanks to its larger core and higher thermal efficiency, the Masata unit significantly reduces intake temps, which means denser air, and more consistent power delivery. Heat soak, a common issue on stock setups during repeated pulls or track sessions, is effectively eliminated. This is a must-have for anyone running a tune on an N54 engine, especially in warmer climates.
To improve exhaust flow and unlock the full potential of the turbocharger, Masata Catless downpipes were installed. This is one of the highest-yielding modifications for a turbocharged BMW—dramatically reducing backpressure, sharpening throttle response, and improving turbo spool.
The catless design is intended for off-road or track use and pairs perfectly with Stage 1 or Stage 2 tuning. Aside from performance gains, it also brings out a deeper, more aggressive exhaust tone—something every enthusiast can appreciate.
The factory coils on the N54 are a known weak point—especially after a decade of use. Misfires, rough idle, and inconsistent performance are common signs of aging ignition components. To address this, the build features a full set of Precision Raceworks ignition coils.
These upgraded coils provide a significantly stronger spark, improving combustion stability under high boost and high load. The result is smoother power delivery, quicker throttle response, and reduced chances of misfire, even when pushing the car hard. They're a small but crucial part of any reliable tuned setup.
With all the supporting hardware in place and the engine refreshed, the final step was a custom ECU calibration. Pre-tune, the car was already putting down a strong 320hp and nearly 500Nm of torque thanks to the intake, intercooler, and downpipe upgrades.
After the tune, output jumped to a reliable 400 horsepower—a clear reflection of the thoughtful mod choices and mechanical prep. Power delivery is smooth and linear, with sharper throttle response, stronger midrange, and no signs of knock or heat-related performance loss.
This E82 BMW 135i Coupe was more than just a bolt-on build—it was a full transformation, carefully tailored to enhance performance without sacrificing reliability. Every part added had a purpose, from cooler intake temps to stronger spark, improved exhaust flow, tighter handling, and better stopping power.
The result is a 135i that pulls hard, sounds great, and feels far more capable than stock. Backed by trusted brands like Masata, EBC, Precision Raceworks, Bilstein, and Eibach, it’s now a sharp, responsive, and truly rewarding drive.
Proud of your ML Performance-equipped project? Share your story—whether it’s a full race setup or a subtle street upgrade—and you could be our next spotlight feature.
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