Just had 4x F1 GSD3s fitted yesterday to the TDI Cupra (225/45/17) - done locally at a negotiated price of 84 squid each fully fitted.
Front set were replaced (GSD3s) 13 months ago and they did about 13K I recon. They replaced the original Pilot Sports, and although I'm no racing driver, the diffence in grip and confident cornering is huge. And since I've had GSD3s, the rear pilots have stepped out a few times, being outgripped by the fronts. So this time I changed all 4, even though rears prob had about 3-4mm still on them.
Super impressed.
I ride a sports bike too, and I know how stupid agressive stops/starts can kill a rear tyre in 1500 miles !!! Smooth it out and the same tyre will last 4000. So those who eat their car tyres in 5000 miles are obviously traffic light race fans with an on/off switch as a throttle.