Do you have any local GI's you know ?, as base dependant you'd be amazed what kit they have!!
The merkur would no doubt be much more softly damped than the eu cars, but would expect spring rates to be quite near.
I'll ask a buddy about the spring rate for the 3 door cos, and merkur, he's a GI but well into his racing stuff, would be surprised if he can't find out in a day or two, so long as he's not somewhere secret as he doesn't tell me jack!!
tabetha