First if all, I have to admit I am biased as Schumacher imports TakeOff Tires.
That said the CS27 has a VERY broad heat range. At the Reedy Race 2 years ago the top drivers were running 13.9 laps in the morning (cool, overcast, very humid) practice rounds with the track at 72deg F. In the afternoon (sunny, no clouds) they turned 13.9 laps on a 140 deg F track.
How did they pull this off?
1. Good car setups. With a good setup you are using the car ability to transfer weight to generate the appropriate traction for what the car is doing. This also preserved the tires as you are not relying entirely in the tires grip to get the car around the track. A good example of this is what we used to run when the Pro-line S3 was the goos tire. Stiff springs and heavy oil with total dependence on the tires to keep the car stuck. Now we have realized that we can be way faster with softer setups that don't over work the tires.
2. Proper tire traction. Paragon Ground Effects when its cold. FX2 between 90 and 140 deg. Trinity Tire Tweak or nothing at all when it really hot, 140 to 180 deg F.
I personally have run CS27's at 160 (Florida in Summer) with no problems. Guys in Phoenix and Tuscon AZ are running them in 180+ conditions, air temps are 104 in the shade!