Back in my pre-Autopian days, I used to use a bug remover (can't remember the name) that said on the bottle "will not strip wax". That stuff would strip the wax off my car faster than anything! I had a black Nissan, and wherever I sprayed the stuff, the paint would instantly oxidize. I think that most tar/bug removers will strip wax.
If you're using Klasse, I imagine a good portion of that would be stripped as well by a tar/bug remover. If you already have AIO/SG, I would suggest just using some AIO to clean the area, then re-SG. You could also try clay -- this should only remove a little SG, if any.