Ok, one step at a time. The exhaust you're looking at might not be emissions compatible in New Jersey. You'll want to see before unloading big bucks. A cat back alone will improve your situation and remain emissions legal . X pipes are also effective but you may need a catted one which is more expensive to remain emissions legal. As far as I know, no long tubes are emissions legal but they do work the best. If emissions is a problem go with shorties or stay factory. A cold air intake will also help. these are the two places most mustang guys start (freeing up the intake and exhaust). I suggest you start slow and see how each mod works instead of dumping a ton of parts in and not being pleased with the result. I would think the 03-04 cobra Eaton will fit your car (DOHC) but it may kill your car. The 03/04 cobra's had forged internals and an iron block built to take boost. You can probably get away with buying a cheap take off Eaton as long as your tuner knows what he is doing and you keep the pulleys stock. I'm negligent if I don't tell you you will probably need more than just the SC. You will probably need the computer, injectors, fuel pump, possibly fuel rails etc. A possibly cheaper route might be to feed her a small shot of NOS. Once again I would remain judicious (50-75 horse) since your internals aren't forged and have someone who knows their shiite give it a tune. One recomendation I do have is get a short throw shifter. These are cheap mods , >$200 and they will improve your shifting and save your
tranny. IMHO throw throw shifters are one of then best feeling mods one puts on their car.