I believe the pro bracket is an x5 compound and the Et street radial is R2 compound. Just looked at those 2 at mcCormac racing tire last friday. The pro bracket is much lighter in weight compared to the street radial as well. Gonna get the ET street radial R for my deal.

http://www.youtube.com/watch?v=aIxaesJ190U

http://youtu.be/lCZAaN7fFLg