[2013 IS]

I have been reading the forum for months and really appreciate and admire all the knowledge base here. I just bought a 335is with very low miles and wish to make some improvements. After reading through many posts here this is my plan. I welcome your collective advice before I go forward.

I plan to ditch the run flats for new tires and buy a roadside kit.

I'm going to add a metal charge pipe with BOV vent into intake.

I'm adding oil can.

Im adding a sealed cold air intake and not the separate twin cans-partly because I don't like that looks. I especially welcome input on this...

I do not at this time intend to alter codes nor get down-pipes because I like the exhaust sound stock. Please let me know what youd suggest and please remark on my plans. Thank you!

[jwalker87]

Welcome to the forum! Most important thing by far is to make sure all the maintenance is up to date. The N54 is a fantastic engine, but will bite you if you don't take care of it. Check out Mike Miller's Old School maintenance schedule. I can't remember if he specifically calls it out, but the N54's water pump has a tendency to fail catastrophically before 80k miles, so replacing it preventively around 60-70k is an expensive but worthwhile investment (and every 60-70k thereafter...).

As for mods, what you've listed sounds like a good start. From there, it really depends on what you want out of the car and what you use it for. The stock platform is very well balanced, so what do you want more of, and at what cost? Willing to sacrifice comfort for better handling, then get some shocks/springs or coilovers. Willing to sacrifice some money (now and at the pump...) for more HP, then tune, downpipes, etc. would work well.

Off the cuff, I'd say brake pads (something like Hawk HPS) and brake fluid (something like Motul RBF600) would be good things to tackle also. I'm not sure if all 335is's were Sport Package or not, but if not then you could probably use suspension improvement like Bilsteins and H&R springs. The Sport Package is already a pretty good balance for street performance (for me at least).

Good luck!

[BSM n54iS]

Get RB's low side catch can kit first then worry about the high side.

[dpaul]

Second the comments from both @jwalker89 and @BdSM n54iS and of course have my own $0.02 to add:

First routine maintenance, then think about what you actually want the car to do, then decide on mods.

It does not sound like you intend to ask much of the engine. That being the case, there is no reason to think about changing the charge pipe. In fact, I've been using my original 2009 plastic charge pipe with 18-20psi boost for 9 years -YMMV but I've had no issues. The stock diverters work fine as well. If you just like the sound of a BOV then replace the charge pipe and install one. It's not going to make your car faster.

There is no reason to install a high side oil catch can. It won't do anything for you - it won't catch much (or any oil) unless you increase the boost. Even then, 95% of the time, you are operating with negative manifold pressures. So consider the low-side system sold by Rob Beck. That catches a ton of oil for me, which would otherwise coke up on the valves (see routine maintenance).

The choice of air filter is up to you. Dual cones is the cheapest solution - the fancier systems won't do anything more for you (other than look good, if you like that look).

In terms of handling, changing from run flats to summer tires or even high quality all-season tires is by far the biggest bang for your buck. If I remember correctly the 335is came with 225/40R18 in front and 255/35R18 in the rear - that's plenty for now. New tires will make a world of difference and is the obligate starting place for suspension mods. Just a suggestion, make your changes one at a time. evaluate what you like and don't like about each change and let that guide the next step.

In terms of performance, just buy the MHD flasher and their off-the-shelf tunes. Install "stage 1" and get used to the vehicle. It does not require any mods and will give you a solid bump over stock. Cheap and safe as milk. You can grow from there.

[tcphoto]

My best mod was ditching the Run Flats and replacing with PS4S', 235/40/18 and 265/35/18 on the Style 189's. I think that the other mods should be kept to a minimum, a carbon fiber M3 trunk lip, Aero lip up front and ZHP shifter knob are mine so far.

[Soden82]

Yes! What is said above. Do the low side can, and do all of your PM first.