The utility did not change the grip of the car, it
increased the weight, which is something that can
be done with several different GP2 editors. It did,
however, turn the sky dark gray.
As far as I know, there is no way to change the
grip of the players car in GP2. The weight increase
does accomplish the desired effect, sort of. It's
not really a satisfying solution to racing in the
wet, though.
Regards,
-Dirt-