Ive never been a fan of GSP vs. Silva either....it wouldnt be a good fight IMO.
Plus the weight difference between the 2 would be ridiculous...Im not going to sit here and bag GSP for the lay and pray because it works...there is no getting around it that his tactic of using his wrestling wins fights, so until someone can combat his strength, why change just to please people who want to see your face look like hamburger meat. While he is winning title fights, he wont change!
Plus with all these super fight theories you are forgetting that whoever moves up or down the weight divisions, that Dana White has said all along that they will have to vacate their belt to compete in the new weight class.