Are you working on a single stage, or two stage paint? If it is a single stage paint, defiantly go for using a pure polish with no paint correction ability like M7 or Deep Crystal #2. After having used both, I doubt you will notice the difference between the two, and DC2 is WORLDS easier to use over M7. Also, check to see if you have any oxidation, because if you do, it would be a good idea to use some type of product that has some paint correction ability. If you are working on a clear coated car, while you will notice a difference from using a pure polish, it won't last more but a couple days and you are better off not using it.
You have a good choice in waxes, though make sure on M21 that it is the second version, not the first. NXT V2 and m21 V2 are INCREDIBLE products that are defiantly better than the previous, with NXT showing the greatest improvement. For a polish with some paint correction ability, the Deep Crystal paint cleaner is awesome and easy to work with for removing minor oxidation, water etching/marks, and previous layers of waxes. ScratchX works well at removing small scratches (like under door handles), mild to medium oxidation, and water spots, and is going to be about the most agressive thing you are going to want to use by hand. I do prefer the Deep Crystal paint cleaner on removing water spots though, and is without a doubt the best stuff I have ever used to do so with.
