If you got 9 years out the OEM battery, you clearly are doing something right. A basic battery seems like it should be fine for you. I don't see any reason you would need a more expensive battery for a garage queen.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |