The pop up headlight miatas have stock spring rates of 150 lbs per inch on the front and 100 lbs per inch on the rear.
I use new spring sets to fit the rear of a 1989 Ford Escort GT/4-door/wagon. They cost about $60 per pair from Rockauto.com
and the rate is approximately 200 lbs per inch. I use the same spring rate all around. The shocks (not struts) are KYB AGX
adjustable shocks.
