Mouse input implementation on Linux

Proper mouse setup is crucial for any FPS game, especially as dynamic as quake. There are many discussions/studies in that matter:

How does mouse input implementation looks like in ioquake3 on Linux platform? Which in_mouse is best for lowest possible input lag? Does running DE (KDE4 in my case) have any impact on in-game mouse settings?

And yes, i have changed usb pooling rate.

ioquake3 uses SDL for mouse input. in_mouse 0 disables the mouse and all other values enable the mouse (all using the same behavior).