ok heres a good start
get your CAI on
go to your local muffler shop and get them to make an h-pipe and put on GT take off catbacks and any mufflers, magnaflow or flows are popular but no pipping bigger than 2.5 because you will lose back pressure. my setup cost around $500 for everything
get a tuner, sct makes good ones
get t-lok (traction lock) it makes you spin both tires when burning out not just the right one

then get gears, 3.73 or 4.10 both will work aslong as they are for a v6 or a 7.5" rear end or option two is to get a gt's rear end (8.8) that already comes with t-lok and just add gears, you can get one off the internet or at a local junkyard for a few hundred bucks
once you get there you will prolly have read enough on this site to know what you really want out of you car and if your going FI or not. good luck modding your
stang if you have any questons just ask and someone will always help you
