The 'dark car formula' wax we used is not actually dark... It dries clear, rather than white, so it is not problematic when you over apply it, or manage to wipe it on to the flat, textured black plastic fenders on the Jeep. Also does not show on our red car, when you wipe it across the rubber for the sunroof.
The one drawback is you need a bright sunny day to do it. Otherwise it is difficult to spot all the places you not rubbed it off yet. Also no big deal if you leave it a bit thick in places.
I don't know if there are any other trade-offs, it still seems to last a good while, nice beading and all, even after the winter.

Chilli Red/White Cooper S, Sport Pack & Sunroof. Delivered June 12th, 2002!
Now with MCS Winter Tire Package.