Will the 285/35 fit? It's very close to the OEM diameter - or at least a lot better than the 275 in the PSS.

SCCAforums ran 285/30/18 Hoosier R6s on all four corners. The only thing he mentioned was an issue at 140 on the banking. That makes me tend to believe the VSC and VDIM will not be too upset by your choice.

 

I don't know if 285/35R18 will fit on the front or not. I have contemplated the same thing myself. Rolling around on the streets with a squared 285/35R18 setup would make it the F version of the new Camaro Z28 . I'm sure 285/35R18s would fit on the rear...maybe minor trimming worst case. I could always order only one pair of 285/35R18s and then try them on the front...if they work, I order another pair and go square...if they don't, then I order a pair of 275/35R18s for the front...or 255/40R18.

Last year I bought 10mm spacers and mounted my rear wheels on the front to verify 275/30R19 PSS tires would fit on a 19x9 +45 wheel in front. I didn't drive more than a few feet with the spacers on, but it cleared at full lock on both sides and looked as if it wouldn't rub under full suspension compression either.

Damn, can you imagine how nice 285/35R18s on all 4 corners with an OS Giken LSD would be? Now all sorts of pleasantries are dancing through my head.

 

Now imagine they're slicks...

 

What about running Toyo R888 all around in 275/35R18? Since I bought a new truck, the ISF is now my weekend/decent weather vehicle. Would the R888s be too much for street duty, not just strip/track? According to Toyo, they are 25.7" and 11" wide with a 10.4" tread width. I'm guessing as long as it's not cold outside they will grip better because of their composition than the Michelin PSS in 285/35R18, which is 25.9" and 11.4" wide with a 10.2" tread width.

I imagine with 3.5mm less tread depth and a soft rubber compound the R888s would wear out much much faster though.