Here is my experience with the films.
Applied 3M film to a Zo6 in 3/2004. The film has yellowed. Had another car done about the same time but sold it before issues arose.
So the Silver vette looks kinda bronze where the bra is. The guy doing this has a good reputation and does lots of high end cars.
When discussing the application for the GT he said that the films have changed since 2004 so in general they are better and more pliable, but the yellowing was linked to the pigments in some ( not all waxes/polishes ). He said that 3M, Avery and Venture all recommend the use of :
Plexus plastic cleaner. I use this for my facemask on my helmet.
www.plexusplasticcleaner.com - cut and paste to yor browser.
I have been paying about $8 something per can at a local motorcycle shop.
It can be used on paint, rubber and plastic trim, I use it to polish and static free coat the underside of my muscle cars. It works great. It will also help take off the rubber from track days. But the best stuff i have found for taking off the rubber was the Wax shop original product. The stuff must be half gasoline, but it wipes it away with ease. You may have some in your stash, try it on the rubber marks, you will like it.
As for the paint looking different after a few years:
My car was garaged 99% of the time. But removing it did not show any super ill effects after 3 years. The car saw nothing but track duty and drives to and from the track. But there was an area that seamed to get sand blasted pretty good, the part under the bra looked much better and there was a visible difference. I took some of the green zaino and a buffer to it. It blended well and you cannot tell the difference.
