I'm starting to think they're all a waste. My car: chambered mufflers, otherwise 100% stock. Buddy's car: 4.10s , intake, full exhaust, aftermarket coil packs, tune, pulleys, long tubes, etc etc. We ran last night and were door to door both times. And I had the same experience with my stock '08 vs my brothers highly bolted '06. So in my opinion, dumping four figures into bolt on mods is a waste. Save the money and go strait to forced induction.