Originally Posted by Taffy66

The GT2 RS has 40kg more weight than the GT3 RS all slung over the rear axle which affects weight distribution and balance. The Spring rates on the rear of the GT2 RS are less than the GT3 RS because of this more rear biased weight distribution otherwise you would have excessive understeer on high speed corners.
This is the info I was given so don't shoot the messenger.

Originally Posted by 4 Point 0

No. The rates on the 2 are higher than the 3. See above.

3 has only 150 rear

2 has 170 rear.

Originally Posted by Taffy66

Sorry for my error. I meant to say the anti-roll bars are softer on the GT2 RS compared to the GT3 RS. The spring rates are as you say harder on the GT2 RS.