I doubt the ECU update is going to do jack for you. The changes are not performance related. More like maintenance to keep up with newer technology from what I've heard. Report back and let us know.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |