Street or R-Compound Tires?

[j.fro]

At our last autocross, the DE/AX chair wanted to show us just what the difference between R-comps and street tires is. He did 3 runs on street tires, then swapped wheels and did 3 on R-comps. The car is a modified 914 with a late 911 SC 3.2. On the street tires he was high 50's...the r-comps consistently dropped 3-4 seconds from his times.

Using R-comps, I can get about 16-18 AX's from the rears (a bit over 1 season), and 25 or so from the fronts (end of the second season is pushing it!) I drive to and from events on these tires, which is 120-150 miles round trip.

Just did the math...looks like I'm paying about $50/event for tires! That's just under $10/run. Nothin cheap about racing Porsches!