"It would not surprise me if MS attempt to use XP SP3 to "cripple" XP......."
I predicted this some time ago and it would be well in line with MS's approach. But whether they would dare to I'm not so sure, for
a) There are so many eyes on MS that it would be rapidly detected and publicised (not that MS care but the DOJ might).
b) It would accelerate the flight to other increasingly popular non-MS OSes such as Linux, OpenSolaris, BSD and Mac. Better that the punters should use XP rather than that.
c) Early tests of SP3 beta releases show a speed increase of 5-7% over SP2.