I've had some dimpled and grooved ones coupled with mintex pads on my S3 setup for about 5000 miles now, as above they can be a bit noisy but it doesn't bother me personally, they stop pretty well and havn't managed to warp, crack or really fade them (and I've given them some stick) for the money I think they're pretty good, I'm running about 270HP and they're plenty good enough to stop the car nicely. Don't know how they would do on a track but I find them spot on for fast road use and for the price I paid I can't complain.