It's just been an hour since this is up and the NA section is sometimes dead. So if you need info fast you should just SEARCH it. But anyways I'll tell you now everything you can do:
-High flow muffler
-You got an AFE so that won't help much honestly because you have a NA engine, what you should have done was gotten a Euro Box intake for N52 or did a simple K&N filter drop in.
-After all the performance mods you should get an AA tune to tie it all together
-Also knock some weight off your car
-Tires + wheels
-Coilovers, don't get springs because stock shocks won't hold it up too long.
-Sway bars, strut bars, etc.
That's almost all you can do to these cars, not much you can do that doesn't require lots of $. Now if you had a 335 those become monsters after a few modding.
| KW V1 | LCI rear | 359m Style | Ventus V12 | AA Stage 2 | Gruppe M | Remus | Mtech Rear | M3 Front |