After some research, I answered my own question. It's completely possible to run a normal coilover on our cars which opens up 10-15 spring choices, some variable rate, some constant. All you'd need to do is buy the QA1 coilovers, springs and adaptors. They make an eyelet to t-bar and an eyelet to stud conversion. It comes out to be about the same price as the GN coilover kit but lets you select one of the normal 2.5" coilover springs. Not sure if anyone else is interested in this but I plan to go coilover and did not want to be limited to 2 spring choices.