I have seen people use that blue painters easy off masking tape. One Guy had magnetic strips cutout to fit.
I use wax left on. When I get home I rub off.
You think this is a problem on a GN, imagine what happens on a white car?
The magnetic stick-on shields worked until trap speed reaches 115 MPH or so, then then they fly off.
So after years of all the "tricks" mentioned here, and a few others, I fabricated "burnout shields" which keep 95% of the rubber and mud of the quarter panel. Works very well for me.
Thanks guy's for all the ideas. I thought about using the magnetic stick ons but I was afraid they would fly off as Nick mentioned. Nick, what you are doing looks like a good idea to me. I think I will try that. Thanks again everybody!