If you want to go fast, get a turbine. RC jets are not very popular in CA because of the risk of brush fires, but I have seen them fly and I doubt there is anything faster in the RC world.

BTW, why is speed so important? I would much rather watch (and fly for that matter) precise, controlled flight. You can only go fast for a short time before you must turn around and come back. Seems like a waste to me.