I finally got my 245/50R20 Pirellis put on and an alignment done. I wanted the STRs, but the STR As arrived even after the discount tire rep said they were STR. At this point I really had no chice as my donut had 300+ miles on it. The big diff I can see is a more agressive outer wheel tread, what ever it is called. I was worried that it would contribute to road noise, but these tires are whisper quiet compared to the OEM Duellers. With the alignment I forgot how nice it was to drive my 9. She handles like a dream. Now just to wait for a snow storm or rain. I will keep you posted.