mod physics

as the mod physics is greyed out in the GPxSET/GPxPatch`s mod settings
how/what can I change to add my own physics settings, I did manage to do it, I think
but when I reloaded the mod it was back to csmphysics, is there a way to make it permanent.
cheers. Mick-S

Rename your own physic in the Name of the Mod Physic

ah didn`t think of that.
cheers.
just another ?
would making the drivers performance numbers similar, give closer racing ?