Not true I believe its on the forum somewhere here but that box is way restrictive. A CAI would be a definite go. A guy on this forum sells headers with and without cat look him up his name is xiaogary. He also has done rotors all the way around along with a couple other cool things. Any and all real serious questions I would ask doax, petrified rabbit or hunteroo. All have good input and lots. of help. As for ultra racing they sell some amazing stuff I got their anti sway and anti roll bars and my car feels like its on train tracks. I went with h&r lowering springs and kyb shocks and struts. Something you could do is the joey mod its pretty cool and makes your stick out. I agree keep with the stock spark plugs. Anything else just pm me and good luck man.