any input on the r888 for autox. ran the stock advans last year ,thinking about trying a 255/40/17 r888.

 

Aren't those 100 UTQG? If so, they won't be competitive in any class if you run SCCA. In street tire classes, you want the best 140 UTQG you can find (RE-01R or Z1). In race tire classes, you want DOT slicks (V710 or A6).