I'd add my praise for the Toyo RA-1 tires. They are, in fact, my street and DE tires on my 911. I use Kumhos only for autocross.

They wear extremely well. In fact, I think they actually wear better on the track than a regular street tire (no chunking on the RA-1s). They are great in the rain, they stick in all temperatures...they are almost without vice. Best of all, you don't have to change tires for DE with them.