I'll echo Bobby, you need to do some reading first. Along with Mike P's articles, you can also check out the Detailin How-To:
Dual Action Orbital Polisher Guide: how to remove swirls, scratches, & oxidation with an orbital buffer. Porter Cable 7424, foam pads, backing plate,
As far as Griot's versus Porter Cable, a lot of forum members like the Griot's because it has a bit more power. However, as Mike P poihnts out, the Porter Cable has plenty of power for what we need to do and the build quality is higher so AG sees fewer returns of these. In the end, which is your preference? Do you like power or build quality?
As far as pads, stick with the Lake Country 5.5 flat pads. They spin much easier than the larger pads, although members with the Griot's machine say it has enough power for the 6.5" pads. Alternately, you can go with the Meguiar's Microfiber Polishing system with their pads and polishes.
I want an sealant on my cars and the last step of the Megs system is a combo polish and wax. So I'd either have to strip the wax and then apply a sealant or mod the last step using something like Meg's 205 polish. I didn't feel like either that so I went with the LC pads and Wolfgang polishes with Menz Powerlock as a sealant and topped with a wax.
If you choose to go with the LC flat pads, you really only need a 6 pak of pads since you're only doing your car - 2 orange, 2 white, 1 gray and 1 blue would be fine.
IF you're only doing your car, I would seriously consider one of the new coatings like CQuartz or Opti-Coat. These reportedly last up to 3 years. If you go that route, you'll only need a polishing combo like the Wolfgang "twins", the Pinnacle XMT combo or Meg's 105/205 combo. These coatings take the place of both sealants and wax. I'll be putting CQuartz on my wife's black Lexus - black, and particularly Lexus, is a bear to maintain.
Anyway, there's some ideas. Now do A LOT of reading.
