Just remember that every car is different. Some make more hp from the factory, some make less. Some respond well to mods, some don't. Also remember that you can't just slap on any combination of parts and expect to make power....you need them to make power together, and complement each other. For instance, if you get an intake that makes midrange power, but loses top end power, and exhaust components that make top end power, but lose midrange power....obviously they don't work well together, and you're going to end up either losing power, or remaining near the stock #'s. Oh, and don't forget about driver error.