I know the sidewall and overall diameter will increase, but will jumping from a 35 to a 40 have any negative effects? I run 265/35/18 on the rear in my GTO, and 235/40/18 up front, and right now it seems tire rack is having a closeout sale on some hankook ventus rs-3 tires and the closest size they have is 265/40/18 for $80.47 per friggin tire. I am in need of some new rears and the price is almost too good to pass up. But i never know all the different effects running weird sizes can do.
As long as all 4 tires are the same, or at least the the left and right being the same size tires, I don't see any issues other that maybe some rubbing if there isn't enough room, and maybe speedo errors.
Cheapo performance tire would still be the Nitto NT05. Still a pretty solid tire for the money. But road noise as they wear could become a bother.
Otherwise for non-track cars, I would rock the Pilot SuperSports all day long. The Pilot 4 S is replacing the MPSS tires. So MPSS should start appearing on the close-outs.
I'm occasionally keeping an eye on the PSS tires because if they hit close-out prices I'll buy a set just keep around for the RS.
For the GTA due to the fat size GM equipped on the rims, 275/40/17's, I don't have many tire choices in that size. So its either Nitto NT05's or Falken 615's.