I just found the mothers nu lens system on Amazon for "limited time" 49% off. Gonna give it a try. I've used the rain-x system on my wife's van and it work great. I don't think it'll work on the g because the hand sanding pads are stiff and probably won't handle the curves on our headlights very well. Mothers uses a drill- polishing pad. And there's some pretty serious scratches that have shown up. The previous owner must have loved the car wash.
I've used 303 pretty religiously for a year and it doesn't seem to be preventing discoloration.

 

In my experience all the products work equally well but an annual refresh is required. At least here in sunny Florida.

 

Glad I lost em before I had a chance to install