Everybody likes a big brake kit and BMW offers its M Performance brake system with Brembo four-piston front and two-piston rear calipers. These require a minimum of 18" wheels and are available in red, yellow or orange. We selected yellow, which is reminiscent of the E46 M3 Phoenix Yellow, as it contrasted our grey paint nicely.

The rotor size is increased from 340mm front, 330mm rear to 370 and 345 respectively. They're also dimpled and grooved to aid pad performance. As a result, they make a slight thrumming sound when applied, which we like.

The kit is supplied with calipers, rotors, pads, heat shields, sensor wires, pad grease and nuts/bolts.

To install, undo the two 18mm front caliper bolts and release the pad sensor wire (it's only on the driver's side). Then hang the caliper safely out of the way. Undo the 6mm allen screw in the rotor and remove. You may need a rubber mallet to persuade the rotor off the hub. The hub should be cleaned and anti-seize solution liberally applied.

We opted to retain the stock heat shields since they were the same as supplied. So simply screw the new M Performance dimpled rotors into place and bolt on the yellow calipers. We used the supplied bolts for the latter, torqued to 60ft-lb.

Insert the pads (after applying more anti-seize to the backs) and secure with the supplied steel pins and spring clips. You can fit the new sensor wire at this point.

Leaving the messy job until last, use a 11mm open wrench to undo the brake line inside the fender well. You want to do this quickly to lessen fluid loss, reducing system bleeding. Brake fluid will strip paint, so clean any spills. The line then swaps over to the new caliper and screws into the fitting.

The procedure is exactly the same at the rear, but now the caliper is held by two 16mm bolts and the pad sensor is on the passenger's side. Re-torque the new caliper bolts to 60ft-lb again when refitting.

The final job, once the hardware is installed, is to bleed the brake fluid. european auto source uses an air pressurized shop system to make it easier, but consult an expert if you're unsure how to bleed brakes. Leaving air bubbles in the line can lead to a soft pedal or even a crash.

Equally important is to bed-in the pads before regular use. This matches the pads to the rotor face to ensure efficient operation.

There are several different techniques but we did it with repeated 60mph stops, allowing the brakes to cool before repeating. Ordinarily, this would give us a firm pedal and powerful stopping but we suspect BMW specified softer street pads that don't require the warm-up period of harder pads. So while they do stop efficiently, scoring well in MotorTrend's testing for its online video we'll discuss next month, the pedal feels a little numb. But that doesn't seem to detract from their overall ability, and they certainly look good, which also helps.


When the car arrived at european auto source we gave it an initial dyno run to record baseline numbers. The N55 3.0L turbo engine in the F30 335i is renowned for getting hot on the dyno, so EAS typically does several runs then allow it to cool down. Taking an average, our car recorded 261hp at the wheels and 299 lb-ft of torque. Not bad considering it's supposed to have 300 lb-ft at the crank!

After the BMW M Performance exhaust had been installed, we returned to the dyno and saw identical numbers. The guys at EAS explained that they'd run an F30 without a cat-back exhaust fitted and found no gains, so they weren't expecting much from the rear muffler.

On the plus side, the etched tailpipes look good, but ours sounded almost like stock. Obviously, you don't want a noisy exhaust, but you do want to hear how you spent your money. However, the M Performance muffler was very close to stock. So with no power increase and very little difference in noise, it comes down to a cosmetic consideration.

After visiting the local BMW dealer, we returned to the dyno to test our new M Performance Power Kit with its new air box and software. The car felt slightly more peppy on the road but it wasn't like the 335is cars, for example.

On the dyno we saw peak wheel figures of 276hp and 295 lb-ft. The power gains come after 4500rpm, with a useful spike from 5500-6500rpm, which means you have to work the car to feel the benefits. It also gets a torque increase at the same engine speed.

What makes a car feel fast is a boost in mid-range torque, which is evident from 4500rpm, but it loses torque from 3000-3500rpm, which disguises the benefits in the mid-range.

People who have driven later 335i models with the same software claim the cars feel faster than ours, meaning our ECU swap possibly didn't release the full benefits of the new software. So overall, for the cost of the exhaust and Power Kit, we have to conclude that the results were rather disappointing. But if you're looking for mods that won't affect your warranty, these are the best options available.

Part Supplier Price
Carbon fiber mirrors BMW M Performance $715 (pair)
Black kidney grilles BMW M Performance $143 (pair)
Exhaust BMW M Performance $1375
Brake kit BMW M Performance $2540 (front & rear)

Next Month We'll test our Project 335i against a modified Cadillac ATS

BMW M Performance
European Auto Source
4015 E. Leaverton Court
CA  92807
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