ours scratches on our driveway too easily... I just pull out a razor blade and trim it regularly to keep it looking clean
I've seen it go on the forums for around $20 + shipping so you could just keep your eye out for that. Otherwise I'm sure a google search of 370z front spoiler or chin spoiler should work fine.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |