New wheels and tires arrived today. Here are some pictures of them installed on the car:
After the first autocross it was clear that the cheap Sumitomo's I was using weren't going to work for autocrossing if I had any intention of being competitive. I bought some used slicks, but only had one set of wheels. Now that I will be driving on the road in addition to autocrossing, I didn't want to have to remount tires for each event.
So after looking around for a reasonable set of used rims that I liked (with little success) I decided to bite the bullet and buy a new set of Kosei rims and tires from Tirerack.com. The tires should be better than the Sumitomo's, and now I can experiment with the slicks on my old 13" rims.