This mouse right here has been tested to be one of the finest gaming mouses made.
I have that exact same one and it is extremely smooth and feels great. The 2 side buttons are in perfect spots and I use them all the time for switching weapons in FPS games. I honestly don't think I could play a FPS game without them.
As for the overclocking question. Overclocking is done from the BIOS before you boot up windows. If you actully have to mess with your hardware it becomes a hardware mod, I myself have not done a hardware mod as it is A LOT more dangerous and voids all warranties. I already told you that overclocking alone usually cannot be detected thus does not void warranties.