Its hard to say since it seems many have used same size tires and some had to trim and some didnt. It also depends on the wheel width. In my experience, a 285/60 on an 8.5 wheel called for front and rear trim of the front well, but that is most likely due to the 8.5 wheel because other have used 285/60 tires without trimming. And better yet, I just replaced my 285/60 Yokohamas with some Nitto Grapplers and even more trimming had to be done, perhaps from the aggressive tread. So ya, I guess you can see where it's a touch and go thing. But remember, you can always crank on the torsion some to avoid some rubbing.
Gary Noonan
'01 S/C VX / '18 Forester XT