First go to Discount Autoparts, Autozone, Pepboys and pick up a can of Aircraft Paint Remover. Spray it with that to get the powdercoating off, then start sanding with 80 grit until its completly smooth, then sand with 120 until all of the 80 grit scratch marks are gone, then same with 220, 320, and 400. Once thats done, You'll need two 3" or 4" buffing wheels, use one first with tripoli then use the other one next with white rouge. Be sure to clean the surface before using each compound. If you can find any sanding bits to make sanding go faster, be my guest to use them
I used a 3M paint and rust remover to get the large grit and surface off. I don't think mine looked that good. The car caught fire, and I sold the intake. I think it took me about 60 hours to do it.