Some entrants in our State Championship have used these tyres and our series runs typically 8-10 lap sprints rather than events lasting 30 minutes to 1 hour or 3 hour enduro's which is what the Audi and Porsche's get in the National GT championship..
They all universally say that these tyres give more outright grip BUT they take a minimum of 2 laps to come up to temp and pressure and are diabolical in the meantime (DM and DH compounds). Given that we only get three-quarters of a lap warm-up before a standing start, most guys using these tyres get swamped off the line and have to come back thru the field in the final 3 or 4 laps.
If you want to use these on track days and/or sprints, then be aware of the time to bring them up to temp/pressure and you should enjoy the result, BUT they do not like a large number of heat cycles - they are heat cycled out after 5 or 6 heat cycles whereas an R-Spec might go 15 or 20 cycles.
The other feedback is that they are grippy, grippy, grippy, grippy oh f4rk and you throw the car at the scenery .... not a lot of warning on the limit and you need to be quick to catch a break-away. The pros love them, amateurs are not so sure especially when getting them up to temp/pressure and right on the limit.
Michelin and Pirelli are both represented at this weekends Bathurst 12-hour for GT's which could be a good watch if you are interested in GT racing ... details here:
Bathurst 12 Hour
and more here:
GALLERY: Bathurst 12 Hour set-up - Speedcafe
There is more on SpeedCafe.com as well .. the 12-hour site also has details of pod/webcast