This may not be of much interest to those that are tracking the hell out of their cars... but I just got back from a 1000 mile trip and the ride quality of the softer GC kit was amazing... totally acceptable ride quality, just seems a touch stiffer....which I like because the car is more planted and performs better.
I honestly couldn't see any reason to spend a bunch more on a coilover kit - especially where many are mediocre or have a track record of significant problems. Just not worth it. Too much risk of ending up with crappo ride quality and I wouldn't want to end up being a test mule for a new product. Just my .02