I think the game is simply hardcoded with a sensitivity curve and deadzone specific for the Dualshock 2 pressure buttons on a regular PS2. Some third-party controls aren't too great to use with PS2 GT games, too.
Patching that is possible I guess, but it would also require setting up some sort of calibration in the game.
Patching that is possible I guess, but it would also require setting up some sort of calibration in the game.