While I used Souveran on my pewter 'vette, I'm currently using Collinite 476S on my pewter Blazer and it looks *very* nice, better than I expected (and I do like 476S anyhow so that's saying something).
That's one paint that 476S looks great on, even though it's not known as a beauty wax. Doesn't mute the flake or otherwise diminish the look at all IMO.
Their 845 only looked a *tiny* bit better and the difference was gone after a few washes; the 845 didn't last nearlyas long as the 476S.
With all the LSPs I have on the shelf, I'm sticking with 476S on pewter.