Yesterday I played against kyuuji as follows:
1. Latest version of Tennis Elbow 2011.
2. Installed Sam Patch 2011 without any .pak files.
3. Latest ITST Patch without .pak file and without build.txt and buildmac.txt.
I hosted the match and on when he served there were quite a few Desync's, which could be dealt with by moving a bit around when returning. On my serve it worked flawlessly, except for that Desync when I hit that smash.
Against Slicer I had no Desyncs when playing with Tennis Elbow 2011 and only "Profiles" folder from ITST Patch. If Sam Patch is the reason for all these problem, then I'd vote for getting rid of it -- I don't need the animations, courts and outfits to enjoy Tennis Elbow.