a new exhaust system, cost-$200, cold air intake-$250, power programmer look at hypertech-$350 and if you want to go crazy an hks twin scroll tubrocharger but that requires alot of work and a pretty penny of about anywhere from $1500-$2000 but do the first 3 i told u, u will gain about 45 hp with all 3 of those and just to let you know higher octance gas does not give you more performance, the higher the octance the higher knocking resistance in the enigne, my source for that is motortrend, hope this helps answer your question