I have the old Logitech Formula Force Wheel and though it doesn't move while standing still on the starting grid, it does tend to want to move from side to side at very very slow speed.
That seems to have something to do with the new physics in GP3 2000. With the new GPxPatch which now has a Physics option, I tried one of the old physics files (2001ferrari-F2001.g3p) that came with Aubrey Windle's Advanced Physics Editor V1.03. That eliminated the side to side behaviour.