3m is garbage use X-Pel. I have 3m on my M5 and it sits in the garage. Only gets 1000 miles a year. I have Xpel on my ZL1 and Audi Q5. It's a better product. If you want the best clear bra search for Suntek. I took some of the Xpel off the ZL1 and put Suntek on the hood and mirrors
http://www.camaro5.com/forums/showthread.php?t=299273