Does anyone know the main difference between the DX3R, DX3S and the Futaba 3PK ? I am looking to buy a new radio and I have a ton of SR3000 receivers that I use in other cars so Spektrum sounds economically best. But, is there a difference between the S and R that I would even notice for racing? Is it worth the extra money for the 3PK? Thanks for your time. I am sure there are other Threads about this, but I do not have the time to search. Thanks again!