Hey there, well, for intakes so far anything I've seen the CAI has created AFR issues, nothing major but enough that u would want your own scanner to delete the code that gets thrown. Something that the dealership would never get you for is the airbox mod, simple, cheep, and creates better flow numbers over the stock airbox as it is. There is a DIY on another site, I will PM you that and more tho.
As for exhausts, unless your tuning the car, a full 3inch catback isn't required, a simple muffler delete would help give you the rumble we all love to hear and be very cost effective, same with the intake mod. Another common mod has been catless downpipes or even highflow catted downpipes, there is some restriction in the stock setup.
See my PM for more info.
