those are definately things i've considered. I've also went out and looked at my car and to my surprise the previous owner put a drop-in k&n air filter on it! though it's quite dirty. I didnt' even know that til now! probably why i'm slightly faster than my friends bone stock 07 rx-8 that and i have an after market exhaust. But all of the advice everyone has said i've taken into consideration. it basically comes down to...do i really need it? is it worth it? So basically if i ever get extra money those are things i have to look at big time. for now i don't plan on doing anything to my car.