I just want to update this thread, after putting many more miles on the car. I still like the sportlines, still think their rate is very close to the stock springs. The other suspension mods have made the car handle much better and drive more precisely. The rearend works so much better, it isn't tail happy anymore, and when it does break loose it goes straight, instead on kicking to one side. It's given me so much more confidence in the car I've spent $ on more power, see my Blueprint head thread. As this is a street car, I haven't had a chance to drive it at the limit and see what it does, would like to know for curiosity's sake, and if I ever do get in an emergency situation would like to know what to expect. Need to find a big empty parking lot, next time it rains and go play.