#1. It would never replace the clay bar in a proper detailing kit, BUT the point I was trying to make is it will make a nice, QUICK way to remove road film and old wax (and the finer swirl marks) after a good road trip. I'm not entirely sure why some people feel the need to pile up new layers of wax on top of old layers contaminated with dirt, oil etc.

#2. When I started, I was treating it as just another car soap. Only after I saw the change in the plastic and rubber trim did I decide to use it as a true finish modifier. When I had my Dodge, and was power buffing it every 12 weeks or so, it was an all-day job, starting with de-waxing with Acryli-Clear solvent and buffing with ReStorzit (3M). Meguires Deep Crystal Polish and, at that time new, Meguires Gold Class Wax. My truck also had a fiberglass tonneau cover that took a couple of hours alone. It was an almost religious thing my wife still doesn't understand.
The point is, when I was doing all that work, I cleaned and polished every nook and cranny, behind the bumpers, wheel wells-everywhere.

As an aside, when I wash out my wheel wells, I finish with a fine spritz of
tire foam. Just a light coat turns it all black, and stays that way for quite a while and repels tar and dirt!