idk what to do.

i want to do more work to my car but idk what to do. i want my car proably around 500 horse or maybe higher but i want it to be comfortable to drive as an everyday driver and obviously street legal cause new jersey is retarted lol. i dont want to put a turbo or supercharger to much money. this only thing that i can think of is a little nos probably a 100 shot but i dont wanna kill my car. Or possibly cylinder heads. Any body got ideas. i wanna keep the exterior and stuff the same cause its an anniversary edition with the actual anniversary package so i want to keep it original as possible. no body kits and shit. the car only has 33'000 thousand miles on it.
heres wat i got done to it already. i wanna say i have around 375 almost 400 horse not sure yet gotta get numbers from track and dyno
PERFORMANCE-Magnaflow full exhaust with x-pipe (2 cats), ford racing 3.73 rear gears, MAC cold air induction, Professional products-intake plenum,space, 75 mm Throttle body, Steeda underdrive pulleys, Pro 5.0 short throw shifter.
STYLE- Interior billet accessories, stock '01-'04 smoked headlights, mach 1 chin spoiler, and "MUSTANG" bumper lettering inserts