personally i wouldnt use scratch X with one of those foam balls...i'd be afraid of going through the paint and down to the metal. Maybe a random orbit polisher, but i don't find those work very well on bikes. I'd try mothers wax with a foam ball perhaps...I really like the way factory paint ends up after you polish the hell out of it with a cloth wheel. to me it just seems...smoother.

with scratchX I get my best results with the Mister Miyagi method. Wax on - Wax off.