I detailed my truck today. No surface prep was required. The truck was pretty much swirl free. I hit it with some Four * UPC and the PC, then followed up with UPP.
http://www.powercln.com/DSC00001_edited.jpg
http://www.powercln.com/DSC00002_edited.jpg
http://www.powercln.com/DSC00003_edited.jpg
http://www.powercln.com/DSC00004_edited.jpg
http://www.powercln.com/DSC00005_edited.jpg