My spare track tires are Sumitomo HTR ZIII's. Compared to true EP summer tires, the sidewalls are soft. Also grip is down. Most EP tires like a bit of heat and start gripping around the temps where the Sumitomos become greasy and chunk. For example:
On the plus side, the Sumitomos are nice and progressive, and communicate (tire squeal) well before they let go. They also have a nice ride on the street.
Great value for the price, but probably won't last long if you're pushing your car pretty hard.