Like the majority of reviews here, they just aren't great tires. I got them when I bought my Mustang and they simply have not held up well; I thought Pirelli was a premier sports tire. I've had 5 flat tires since I got them and lost one because it could not be patched up. They're comfortable to drive on, but they certainly lack in overall handling, cornering, responsiveness, and snow isn't even an option (forget about it); wet weather is semi-dangerous. My biggest fear is hydroplaning. I've never experienced such a loss of control driving through even modest puddles with these tires; I always thought it was the Mustang's handling until I switched to Ohtsu FP7000's, which handle amazingly in rain.
Summary: Try the Ohtsu FP7000's; they are half the price and perform a lot better. No sense in buying such an expensive Pirelli tire.