I too am looking at buying a set of coilovers this off season, as my AGX's are starting to go away... again. I'm setting it up as a track day/future TT toy, so I will not be at all concerned with comfort.

My tentative pick at this point is 675#/550# (12/10 kg). At this point my concern would be balance, or more like I don't want it to oversteer on neutral throttle, like in sweepers. I've got a 1" rear sway/stock front, with 450/350# springs, and she pushes, but not badly, I can always get a little more rear spring later, if need be.

If anyone is road course-ing a similar car and has some insight on a setup like what I described, I'm mostly looking for a complimentary rear spring for the 12 kg fronts. Thanks in advance!

I was wanting to know the same thing actually. I want to find out what spring rate will be best for road racing, then estimate how low I'll be going, and from there figure out if I will need fender flares to keep my tires from rubbing.