I'm not disputing what omegavx has said, but I am perplexed by it because it has never happened to me. I live in the land of the practically guaranteed afternoon summer showers, I've been using it (Meguiar's purple tire gel - Gold Class Endurance High Gloss) for well over a year now, and I have never had any problem with it on the paint. Granted mine is an astral VX and it could be less apparent on the color, but I am certain that there isn't ever any residue or discoloration on my hood or rear door. Maybe it's different waxes we use or something - I have no idea. I used Zymol before but a Mother's carnauba wax came with the clay bar and I used that the last time I did it.

I just wipe it off with practically no trouble if I get any on the paint during application. I know a trace amount will run off in the rain, but mostly it repels the water quite well with a fairly fresh coat on it. I'm not into the greasy look, so through trial and error I have perfected a technique for applying it and I use the minimum amount necessary for full coverage and rub it in pretty well. Then I go around again wiping off any excess I may have left. The same goes for the insert. I'll also do this on a weekend when I know I can leave it in the garage for a day or so to "cure" before running a chance of getting rained on. This will keep it will be looking good for a couple of weeks.