My rx7, fully tuned to 550pp does 8:29 on SS tires at Nurb 24. I must be an alien I'm actually easy to please, but those race series you talk about confirm exactly what I stated "Strict limitations" Many of them or no tuning series, or a one car series. Not on to be stubborn without backup, I tried to break the Tsukuba track record on SS tires in a street car. I limited myself to 800hp (as the current record car is) and I chose my 650pp Z06. 53.1..I'm off by a second. So, I stand corrected, the sport tires at least seem to be fine. Now, as for the slicks...Well, they made up a 100pp difference and ten some. My 550 Audi R8 Destroyed the lap record with a 51.5. The same car on SS tires was in the 55's ... 4 seconds on a 1 minute lap from just tires? That seems out of whack to me. I need some data to compare against. As for the tires, CS ... even SH and lower are a great way to keep the riif raff out of the room. I personally REALLY enjoy CS tires up to about 500pp, and SH beyond that. What I am stubbornly defiant about though are the gross imbalances (Ferrari Dino) and the CRAZY top speeds. Both items that should be EASILY addressed, but are constantly over looked.