Not sure about the Porsche stuff but it seems a little pricey.
I picked Renovo and 303 because they both had great reviews. Plus, Renovo is the only paint on waterproofer I am aware off.
Raggtop seems good, and lot of people use, but I prefer the paint on waterproofer. From what I read 303 seems like the best cleaner. The Renovo stuff is expensive, but I didn't have to tape off the car, and it went on much thicker than a spray.
