yeah free flowing exhaust. but not the loud ones. headers, that is low restrictions but never compromises the backpressure (read torque). of course, engine power is not about horses only, but torque too. ecu upgrades, then brakes. ground effects too, but not too loud. duck-tail and chin spoilers will do... oh by the way, before aesthetics, don't forget a stiffer (not necessarily lower) suspension and shock absorbers to carve out those corners...

go(d)speed!!! :D