Been running my SP1 for a few months now, but had been using Pardus tires that didn't work well on our track.
Last meeting I tried Ride R1 on the rear with Pit 573 fronts and the car was transformed. Had great drive out of the corners, could pretty much mash the throttle. Still needed some more steering, but the car was set up around needing rear traction from the Pardus tires. Had a pair of Pit 574 soft fronts to try also, but had a huge/freak accident before I got that far.
I ran slightly wide coming on to the back straight and rubbed the poly pipes. Never an issue with my touring car, but with the large sidewalls on F1 tires it climbed the pipe and ran along it until it found one of the bolts anchoring the pipe to the ground. The following accident was rather spectacular, car flying in the air, rear wing removing itself and landing on the other side of the track a good 15 metres away!
The aftermath of this wasn't pretty, a number of parts will need to be replaced. It snapped one of the Associated side links, snapped the thread from the roll damper shaft, pulled the pivot ball out through the back wall of the 'football', lost a side spring, damaged a side spring holder and delaminated many layers of the rear carbon pod where the side link mounts on one side.
Of all these parts the only one I had in my spares was the kit spec side links, so I was done for the day after just one race.