I suspect tire threads will drive opinions almost as much as oil discussions. I had Hankook summers on both XFs and after ~20k miles I still had plenty of front tread, but the rears were 6/32s on the roadster and less than 4/32s on the SRT6 (I was enjoying spinning them too much). I decided it was better to be safe and replace them at 14 years old (the tires, not me).

Decided to shoe both in Continental Extreme Contact DWS06 Plus, 235/40-R18 and 285/35-R19. I wanted the extra width to protect the rims. It set me back $2050 after rebates but they are a 50k mile all-season, look nice, ride quietly, and the grip seems excellent for the fair-weather but fast driving that I do. I will let you know in about 10 years how they wear and if they remain quiet. By the way, the same tires in oem sizes were only $1608 for the eight at Discount Tire.