I have a friend who is on this forum as bimmerjim and he has a turbo e30 with a t3/t3 .48/.42 with the neccessary fuel mods and crap like that. I know he has changed turbos to a .63/.60 if I remember right and is running slightly less boost than on his old setup. PM him and he can tell you all that you would like to know. Also check out www.e30sport.com