now im going to pick on lukes a bit.
really only around 50kgs between the models, dont forget to add 20kgs for autos and 20kg+ for sedans
1992 R32 GTSt = 1320kg
1997 R33 GTS25t = 1370kg
2000 R34 GT-t = 1410kg
the34 turbo was going good for around a year at 11psi, only let go after snapping (and i mean snapping) 2nd with semi's. + i got it for a case of coke'a'cola as it was on its way out.
with the extra 30kw and 30nm between 32 and 33 (flywheel) and extra 100mm wheelbase you wouldn't notice the difference in weight, as luke said