Air Filter
Air Filter - The easiest and fastest modification is a high flow air filter. High flow gets more air into the engine and if you have an upgraded exhaust, more air out. High flow air filters are defiantly where you want to start.
Air filter
Performance Boost: 5-10 horsepower
Supplementary Modifications: Cat-back exhaust system
Note: A high flow air filter will add performance with or without a cat-back exhaust system.