Originally Posted by BreakPoint
None I can think of.
Agassi did switch to a SMALLER racquet late in his career though and won a lot of matches with it.
Agassi went to a 102" Prestige mold for a bit during the Liquidmetal line, in comparison to his usual 107" Radical OS mold, is a minor size difference if you hold the racquets together. Also around that time frame, he used a 102" Liquidmetal Instinct, again not much of a size difference when you hold a 102 and 107 next to each other. The last slam he won was the 2003 Australian Open where he was using his usual Radical OS.
As for what Jim Courier said, well he was always a PS85 user and only recently switched to the larger head Donnay racquet, so it's not like he's talking out of butt...and I recall Sampras recently saying he shouldn't have been so stubborn about his racquet.
My take on this: Federer doesn't need to change racquet size at the moment...maybe later on in his career say if he plays into his mid 30s...maybe doing what Sampras did and go to something like a Blade 98.