Thanks for the info and the clever spring rate approximation technique. Unfortunately, I don't have these springs in hand to try it and the owner knows noting as to rate. He acquired them years ago and never used them. By std 3 door (cossie) springs, I suppose that means compared to RS springs. My guess is that the Merkur XR4Ti is heavier than the Cossie models, and that the Merkur was sprung light for a softer ride in our market. I've read that the "progressive" springs used in the Merkur went from 250 to 500 lbs/in with about 250 used up when it lowered off the jack to static height. What I am now trying to determine is whether the 3 dr Sierra Cossie springs (which I can acquire cheaply) would be stiffer than Merkur stock. The Cossies are about 3.5 inches short and of thinner diameter stock. I'm guessing that they would be and may use them as a starting point...maybe more spring sets to come.

I had not heard of the ahmed springs but do know of some cars with AVO springs and more with Eibachs. The Ahmed spec LEDO springs might be ridiculously expensive to ship.