I had 4 fitted a couple of months back and found grip very much improved, as a result I think that, when I'm in the mood, I actually push harder than before I and have felt some slight pogo-ing. As if there isn't enough rebound damping. I dont think its my suspension, I think its the tyres, but as I say, it could be because im loading the sidewalls more round the bends.
Overall though I'm very happy with them. They also make nice squealing noises