The Deep Crystal line is the basic stuff, not the best shine (or best for removing swirls). Basically for the guy who does it once a year.
I've used the Meguiars Fine Cut Cleaner, Dual Action Cleaner/Polish, Swirl Free Polish, and Hand Polish (can you tell I like Meg.?) These are different levels of cutting, but if you get the DACP, you don't need the FCC. Then it goes DACP -> Swirl Free Polish -> Hand Polish. These aren't miracle products but give very impressive results, even just applying by hand (which is what I do). The difference between them and the Deep Crystal is like the difference between an F1 car and a kia.

As for the clay, I've used Mother's, Meguiars, and Clay Magic. Hands down the best is the Clay Magic. (Conveniently it's also the cheapest). The Mother's bar requires Olympic strength and endurance. You'll be done in about 3 hrs. The Meguiars bar, I had the same problem as placo1 - residue all over the bumper. I used a full bottle of lubricant trying to do half my front bumper. The Clay Magic required no rubbing back and forth til your arm falls off like the Mothers (and Meguiars if you try to 'pick up' the residue left with the bar). 30mins on the whole car top to bottom and I was done. I even did the wheels.

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1984 300TD Turbo 156Kmi
"He who seeks knowledge begins with humbleness" - Buju Banton