First off, I've found this tire to be louder than most... but, this is on a sports car, so I don't really care.
For many years I've used the Michelin PS2s, and been very happy with them. I decided to go with the Dunlops based on a few recomendations and their slightly cheaper price. I don't usually track this car, because I have a race car with Hoosier R6s, but once or twice a year there's a HPDE event where I can't bring the race car - so I drive the 996 with the PS2s.
Well, I just came back from driving the Dunlops on the track, and I'm really impressed. They held up at least as well as the PS2s and they were quite grippy. I'm convinced, for track duty, they're about the best regular street tire out there.
I've driven a number of other street tires on the track over the years, and too often the first few laps feel OK, but the rubber compounds and/or tire construction just can't handle the heat. After 10 minutes or so, it's like sliding around on snow tires.
Sure, you can feel the Dunlops' grip falling off a little after 30 minutes, but it is still a street tire - it's not magic! I'm just saying it's the best street tire I've experienced on the track.