If a set of G3 intakes is too expensive, then you have essentially already maxed out your power. A proper cold air intake is the logical next step as well as your least expensive next mod. After that it's porting and headers and cams (expensive parts with more expensive labor). Some of the parts might be affordable if you can DIY the installs.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |