I tried the 1000 hz hack, and my USB ports couldn't handle it, you just re-install the backup you made before you changed it, and nothing happenned.
I use USB on all my gaming boxes, I think I'm lazy and there are still one or two that have ps2 adaptors on the mice.
My personal advice on it is to try the ps2 port first, increase the sampling rate to 200 hz and notice the smoothness.
It will be like when you first used an optical mouse, you'll just play with the mouse for a while, hehe.
Settings -> Control Panel -> Mouse -> Hardware -> Properties -> Advanced Settings -> Sample Rate
Make sure you use the ps2 port to try this out.
If you notice a big difference, game on it for a few days, if you like it like that, keep it ps2.
If you want more, I'm sure I can point you in the right direction to hack your USB.
BTW, you'll want a mouserate checker to make sure that you got what you think you do.
http://tscherwitschke.de/mouseratechecker.html
I use that one.