Wow where to start. First of all go get the magazines Muscle Mustangs & Fast Fords and 5.0 Mustang. Or google there web sights and check them out online. They are like a mustang bible. You didn't include how much money you had to dump in it so i will assume your on a budget. I would go with a hi flow cats/ exhaust system, cold air intake, pulley set, hand held programmer (not one of the p.o.s on ebay) from like diablo or super chips, if its a 5 speed get a short throw shifter, 3.73 or 4.10 rear gears (4.10's will make it faster in a stop light to stop light race but it will take away from your top speed), and a 50 to 75 shot of nitrous (they say 125 is safe for a bone stock motor but i like to be on the safe side). If you ever plan to upgrade the wheels try to go with 10 to 11 inches wide in the back (295 to 315 tire size). Mustangs are great, good luck with it. It becomes a way of life. Oh yeah go to summitracing.com and jegs.com and sign up for a FREE parts catalog.