My plan for the car falls into the following three main categories: Performance, Suspension/Dynamics, Appearance.
Note: the list of modifications & parts are not listed in any particular order
1) Performance
- Intercooler: Cooler air = more power, and lower operating temperatures. A larger FMIC is a quick drop in, taking no more than 1 hour of work and will help to keep engine temperatures down and will really shine when working in combination with a tune.
- Mid pipes/Exhaust: A simple way to open up some flow for these cars is to replace the secondary catalysts with a mid-pipe or installing an exhaust system that replaces the entire exhaust system from the downpipes back. Simple axle-back systems are purely for looks/sound but a full down-pipe back system have shown 10 hp / 10tq to the wheels with faster spool times. An additional benefit would be 20lb + weight reduction.
- Drop in air filter [Installed] : The stock intake box is already a decently designed 'cold-air' intake. Replacing the stock restrictive filter with a higher flowing one is a simple replacement/maintenance item. Don't expect a big bump in performance over a fresh paper filter, although I did notice 0.2 - 0.4 mpg improvement combined over the same driving conditions.
2) Suspension/Dynamics
- E92 coupe rear brace - Bolt-on OEM upgrade for sedans that were factory on all coupes. Easy, inexpensive chassis rigidity upgrade without damaging ride quality.
- M3 bushings - Simple drop in, OEM fitment which will tighten up the rear-end
- M3 rear control arms [Installed] - Significant improvement in the rear end and highly worthwhile modification with no downsides. 5 lb unsprung weight reduction. (see review for more details)
- Springs/shocks/strut conversion to sport package (dropping the ride height 10mm) - better turn in and reduction of deflection mid turn. No significant decrease in ride quality especially when paired with a removal of run flat tires and light weight suspension components.
- Stainless steel brake lines - Simple, cost effective, improves pedal feel improving ability to modulate pedal and to initiate bite on brakes
- High performance tires [Installed] - Easily the most important thing to do on this list, especially when you switch from run flats to conventional tires. This should be the priority for any enthusiast.
- Cowling delete/modification - approximate weight reduction of 10lbs
- Light weight rotors - lifted straight off the z4 35is, 2 lb reduction in weight per corner, will not rust and better heat dissipation qualities [Installed]
- Brass calliper bushings - improve directness and feel in braking, more even rotor wear and improvement in the ability to modulate brake pedal with an improvement in initial 'bite' into the rotor
- ECS lower trailing arms - Bolt on light weight aluminum trailing arms. Significantly stiffer than factory with a slight drop in un-sprung mass (2 lb). Not a critical component but a good way to round out a suspension upgrade.
3) Appearance
I personally believe the m-sport package is the perfect look for this car and that really means that I don't have much planned as far as appearance modifications planned. The major plan will be to mount my license plate using the front tow hook and removing the center mounted bracket. This will make for a more aggressive look and help improve airflow over the intercooler and radiator.
Additionally I plan on removing the sidemarkers and replacing them with painted markers.
The final and perhaps major visual improvement will be to do a full 4 stage detail on the car which will really help restore the exterior after its 100k km life and refresh the look of the car and get it ready for events over the coming year.
Conclusion
The 335 is a fantastic performance sedan, the modifications planned in the three areas with a particular focus on dynamics will serve to take the vehicle to the next level without destroying is character or impeding the ability for it to serve as a daily driver. Carving corners and putting power down is easily one of the highlights of the car along with the phenomenal drivetrain. Enhancing the dynamics will be incredibly satisfying alone and will also serve as a strong foundation for a 'power' build later. Completing the suspension/dynamics will give a better understanding of how much more horsepower the chassis can handle, and realistically "it is so hard to make more power on the n54" is not something any enthusiast has ever said.
