I'm about to make my first big purchase and before I go spending a bunch of money, I was wondering about the P21S wax. It says it's great for red, black, and other dark colors, but my truck is pewter metallic (it's a silver/gold color). Are they saying it's great for those colors, and ok for others, or are they saying if you don't have those darker colors you're wasting your time? Being that my paint is metallic, it looks nice but doesn't seem to shine as well. I just want it to be as shiny as posible.