I use the 3-step perfect-it system also, including their 3 different color polishing pads. I wet sand with 1000, 1500, 2000 and finally 2500. I agree that 3M has gotten expensive, but I think it is worth it. If you want to use a quality prodct at a decent price, look into Maguires polishes and pads. Prices are considerably lower, and the product quality is great. Plus, you can buy it at most Big Box car parts stores.
