Also posted this on the other Ohlins problem thread:
As an update, I picked my car up from TC Kline today. My only regret is that I didn't just buy his suspension setup from the beginning. He installed 400lb/in (70NM/mm) front and 700lb/in (123NM/MM) rear. Fronts are 7" (about 178mm) and rear are 10" (254mm). All 2.5" ID. They are customer made for TC Kline by Hyper Coils (
www.hyperco.com). Original plan was 600LB rear and 300 front, but the ID wouldn't work on the Ohlins for the front. This set up is pretty close to his M4GTS. He resprung that lower than OEM.
Interestingly, he did not have to reset ride height. This tells me the new springs are holding the car up and at least not too soft to cause it to sit lower.
I have only driven about 20 miles since but it is significantly better. Straight-line stability is as good as OEM or better and overall ride is a bit more firm but not uncomfortably so. No more constant steering corrections due to rough pavement or bumps and rear is a bit more planted.
Really nice guy and it is really valuable that when I call, he almost always answers. Especially since he is local to me.
For reference, the Ohlins springs I had were 230NM/mm rear (1,311LB/in) and 200mm and front was 90NM/mm (513LB/in). This was the rear spring recommended for M3/4 vs 190 for M2. Not sure why this was on an M2 Kit...