As far as I know the only way to get show room shine from a rotary style buffer is experience. If you're insistent in keep a rotary buffer in your process, why not just supplement the rotary buffer for cutting/polishing with a random orbital for your finishing step?
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |