I've put the VanSteels on my C3...However it (the car) has only been rolled out of the garage a couple times. I'm going w/ the semi-coil overs on the front from VanSteel as well. Really nice stuff- just a little bit of welding the shock mount- reinforcement slides over and just weld it to the frame. The rear comes w/ the offset trailing arms. It was no problem at all w/ the install.
I haven't seen ANYONE complain about the guys at VanSteel-they also did my wheel bearings and bolted it all up to the trailing arms for no extra charge.
Richard