Nexen Tires
I decided on Nexen CP672 tires in 195/65R-15 size. These are H rated for speed and 91 for load, which are pretty good numbers. The H rating means that they are good for a sustained speed of 130 MPH, so I guess I'll have to be careful not go too fast. The Nexens are well liked by Porsche enthusiasts and highly rated by Consumer Reports. I would have liked to get Vredestein Sports, but they are $100 more each. I can't imagine that they're $100 better.