Top 5 go-fast mods;
1) UDP
2) Intake
3) Optimized Throttle Body
4) Exhaust
5a) if auto - chip to firm up shifts
5b) if manual -
Top 5 handling/braking mods;
1) Brake Package from Stazi
2) Stainless Steel Brake Lines
3) 19mm Rear Sway Bar
4) Rear Strut Tower Brace
5) SVT Motor Mounts
Top 5 other mods;
1) Ford Motorsport Plugs
2) Change Oil to Mobil 1 5-30 Full Synthetic
3) Hood Lift Kit
4) Foglight Mod (or add Foglights)
5) Sylvania SilverStar High Beam Lights in low and high beams
Top 5 appearance mods;
1) Rims/Tires
2) SE Sideskirts or SVT bodykit
3) Lip Spolier
4) "Knauberize" and remove badges
5) Springs/Struts
There are many other mods to be done, but this is what I consider the best bang for the buck mods that will give noticable results.