FYI, there are absolutely no mods required with 285/60/18s, you'll just experience very mild rubbing and possible wear of a couple of areas of the wheel well liner only under full compression or steering lock, that will quickly fade as the tread wears out just a bit. As a matter of fact, the overall circumference and diameter of a 285/60/18 is fractionally smaller than a 265/65/18, so a 285/60/18 will actually be an easier fit - although still partially deflated - in the spare wheel well under the car than a 265/65.
The one "disadvantage" of the Grabber AT2 in that size is that it's an "E" tire, so you will trade a virtually indestructible sidewall and LT load capabilities off road for a very heavy tire that's likely to run noisy and stiff / uncomfortable on the road, as all E-rated tires normally do. A bit too much of a compromise for my needs, but from an off-roading perspective that tire must be right up there with the best of the best ATs (and it's snowflake rated and studdable for severe winter use to boot.)