I understand, but 99% of the aftermarket stuff out there doesn't really provide any significant benefits. You have to ask yourself..How much $/hp gained are you willing to pay. $300 for a CAI that "might" give you 7 hp? Is that really worth it? $400 for a chip that will void your warranty and give you 10 hp at the expense of mileage or emissions. Is that worth it?
I know I"m raining on your parade, but I just feel that the younger E90 owners need to be fully informed about these "mods". BMW engineers your car with the best combination of power/performance/reliablity at a fair price..(well maybe no so fair). Race cars do amazing things, but they need to be worked on ALL the time.
My best advice is to save your $$ and in about 6 yrs you can pick up a nice used E90 M3, that'll give you all the power you'll want.