Thanks for your reply.

I have 17k miles on original front and original rear tires. Rears appear to have about 6/32 left on them, fronts around 4/32. I'll probably replace the fronts at around 20k miles, we usually have a bit of rain here in the fall. I'm contemplating putting something else besides the Sport Maxx's up front, and replacing the rears with the same tire when they're due. I don't think there's any harm in that? What about if I went with non-RFT's up front for 5k-7k miles before putting non-RFT's in back as well?

I am looking into the ex warranty now because I know I'm going to keep this until it hits 100k miles, and I'd like to lock in the ex warranty cost now rather than 3 years later after the MSRP increases $500.

I worked in Buick's experimental engineering back in the 80's, and we were stuffing the Grand National's 3.8 turbo into anything GM made just for the heck of it. We somehow got the motor into a Trans Am, and thus the '89 Trans Am turbo was born. GM brass picked up on it, and outsourced the work to another company for the production run but it was our idea originally.