I have run a D&D rear coil-over set-up, coupled with lakewood drag shocks. I ended up taking them off and saving them for my notchback, so I don't have any input on how they performed at the track. As far as whether or not you should install one of these kits, I would say it depends on what you are using the car for. If you want an all-around car, then I would say stay with a factory style set-up and progressive rate springs. Otherwise, pick your coil-over spring rating and go with it. It is a pain to change springs out regularly!