Mate of mine wanted a clear tank protector, but like fizzwheel said he found they go yellow with age.
My Toyota Yaris has a patch of clear plastic protector just in front of the rear wheelarch, where the cr@p from the front wheel hits the bodywork. He priced one up at £10 from the local Toyota dealership, same as a tank protector, and it doesn't go yellow. Trim to required shape.
