Johnny,
I use Meguiar's caranuba gold class wax on my black boxster. It makes it shine like a mirror! I use the paste wax, but cannot vouch for liquid waxes. I am sure mothers is the exact same all in all when it comes to paste waxes, but I used meguairs as I like their in-car cleaning products. It is a no frills wax, but does a damn good job for $10. I have heard zymol is an amazing wax but I am unfamiliar with putting a cleaner wax
on my car.