Scottwax- Interesting about the Souveran holding up on the black Excursion. I'd found that I had to reapply it more frequently to the hood of my XJS, which gets pretty hot, but your example/experience is better by far.
I must say that I never got that kind of (2.5 month beading)durability out of Souveran on a driver, though. But then we're in different parts of the country.
Oh, and FWIW, I recall a recent post about how #16 held up well in the SW too.
SLiM003- Some of those synthetics looks awfully carnauba-like, but if you want to stick with a "real" wax, OK. *I* found a very striking difference between P21S and Souveran on my (silver/gray metallic) XJS. It really surprised me how different they looked and I really preferred the Souveran (but that's just me, and I only tried the P21S on that car).