Porter cable makes a da sander, and a da polisher. It depends on which one you're looking at. First of all, I am assuming that you want to color sand, and polish your factory paint. You never want to use a power tool to color sand a paint job unless you painted it, and you know how thick the clear coat is. You want to wet sand it by hand with a couple drops of dish soap in a water bucket. Start with 1500 grit, and then go to 2000 grit. if you want to make it faster to compound you can use 3000 grit trizact pads by 3M on a DA used wet before you compound. They are very expensive though when you have to buy an entire box. Compound with a rotory buffer at a fairly low speed, and polish at a slightly higher speed. My best advice is find something to practice on first, like a junk yard hood. If you start with 500 grit you will end up needing a paint job, same with using a da to sand it. You need to be very careful. Factory clear coat is really thin, and it doesn't take a lot to remove it.
