I LOVE the R1S but have not run the R1. I run them on my T4 Mustang and they work wonders. Now the Mustang weighs in at 3450 so its quite heavy for the tires too. I can usually get a race and qualifying session in before I need to replace them. Talking with the engineer's from BFG..there is no need to heat cycle them before using. Just scrub them in for about a lap and then go. They hold up really well and are consistant thru a race. If they start getting too hot..you will know it. Back off for about a lap or so and then right back to it.