Keep the engine at WOT and 5K+ RPMs... if you go around a lot of turns like this, it has the added benefit of wearing the tires out faster so you can replace them with something that is quieter. I am happy with my Nitto Invos, but noise reduction wasn't a factor in my decision.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |