Intake, Exhaust, Header, Sway bar front and rear (progress is that way to go here)...Most will tell you to lower your car but i'll tell you that if you love your car, dont lower it, it just makes every little rattle worse and worse until eventually, shit starts breaking, even on an 07. Intake, exhaust, header, and sways will run you from $500-$1000, from there i would say to get larger rims, and if you dont have an ex do the drum to disc swap, its not that difficult since the ex has them and they offer much better braking. and then from there you can do some N/A engine work if you wanted (cam, Valvetrain) or you can go turbo or you can drop in the K from the Si without much trouble, but for just come more fun i would say to just do intake, header, exhaust, sways, rims, brakes, and cam if you want. good luck!