All I have done to mine is the CAI, and that made a noticeable difference to me. I have thought about doing the exhaust, but I like the fact that my car is quite, and I don't want to add an exhaust that would make a lot of noise. I want the car to still sound like a luxury vehicle, and not a rice rocket. I bought a shark injector on ebay, but the person I bought it from used it on his own car, and then lied about it when he sold it. Since it can only be used on one car, I got hosed on that deal. I'm still trying to get my $200.00 back out of that one.
Trying to take over the world since 1981
RIP 330ci - Current: B5 Audi A4, e39 M5