Powerboats Reports in Oct 2004 had the results of their wax test that was done over a year in New England, outdoor exposure. They took a permanent marker, put it on a gel coated surface, then waxed and put in sun for a year. They examened the fading on the inked part to determine how well the underlying gel coat was protected . The results were from best to least: Collinite 885 Fleetwax, Turtle paste wax, BoatLife paste, Meguiars Mirror Glaze (paste) Starbrite Paste, 3M paste, West Marine paste. Liquid waxes were all secondary to the pastes but two non-wax coatings did well too. They were Poli Glow Liquid plastic and West Marine's Teflon.
I have personally used Meguiars Mirror Glaze Mold release wax on my cars during my boat building days here in NY area, lots of salt during winter and had excellent results. I figured if it was good for releasing fiberglass hulls from a mold after being exposed to styrene and mekp in the polyester resin, how bad could it be for protecting the cars ? It is a bear to wipe off however and I have stopped putting this much effort into finish maintenance on the cars.
I used Meguiars Liquid Gold on my CD25 in November and will use it again after they turn the water on at the dock and I can wash the winter grime off the boat. I plan on waxing my boat surfaces more than once a year and the Meguiars liquid goes on and off easily. (it smells nice too)
Regards,
Peter