Well I have my Thrustmaster RGT Force Feedback Pro wheel rigged up now, and managed to get down to a 1.38.50 ish.
I think my problem is mainly with the racing line - I think I am turning in too late on corners. The problem is, if I turn in too early and I clip the inside curb too heavily, then on some corners that can cause you to flip.
I guess its practice practice and more practice as you say!