Purple haze is a great wax for dark colored cars. I prefer the Blue Velvet though as I like the hard waxes myself. I have tried it on several colors and have found that, while not tinting the colors all that much (unless you put several coats on) the waxes look their best on the colors they were designed for. (purple haze / blue velvet = dark, Banana Armour / Orange Crush = warm mid tones).
If you want a good all around wax from them for all colors that is not charged, then diamond white / light fantastic, rainforest rub and hard candy are great options!