Urethane is the the most technologically advanced paint available and has the best chip/scratch resistance and UV protection. There is a new even better clear that just came out made by DuPont. Its about $12 for a 16oz can and it the best stuff in the industry out of a spray can. You can get some by calling 1-800-548-4321.... the website is
www.paintworldinc.com but its so new they dont have it on the site yet.