I use Reflect-a-Cool from Agriemach.
The top layer has just separated from the rubberised layer on my Plus 4 after 3 years, but the rubber was intact. There are some pics on my AR exhaust post.
On my Roadster, I cleaned the wings and added a layer of Wickes pretend lead flashing. It's a self adhesive plastic, and put Reflect-a-Cool over the top. That has stayed put but the wing has to be cleaned well. I used white spirit.
