what is wrong with playing smaller head size? ps85 or K90?? it seems so sensitive with alot of people in this forum. It does not matter Federer playing with ps85 or K90 or with some paintjob, it is all matter how their games or your games improve with the racquet. you can play with a 60 square inch or a 120 square inch if you games improve. It is all about the beautiful games tennis not about the racquet or Federer. By saying that, I do look up the pros racquet specs and setup since they are best with what they do. I setup my K90 with Fed setup and yes, I is truly amazing compare to my own setup. I played great with many tweener racquets before or off the shelf racquest at BIG FIVE which include Wilson HyperHammer 2.7 (28" long & like 260gram), Head flexpoint S6 (102 square inch), but I also play well with Andy Roddick Pure Drive plus (100 square inch) and now I switched back to the K90.. I play my best with the K90 so far regarding my knee injured or I even add a few more gram into the racquet. So learn from the pros but suit what best for you and not so sensitive or machos about the racquet size. It's all about Tennis and you..