drowd - The real issue is the swing arc of the tire, in other words, the arc made by the outside of the tire as you turn the steering wheel back and forth. The arc is influenced by three major factors: section width (the 265), overall diameter, and wheel backspacing (how far the wheel sticks out from the hub). Different combinations of these dimensions will result in different arcs, which will in turn require different levels of cladding trimming.

As an example, I have 265/60/18 tires on my VX. That makes for about a 30.5" diameter, which on an OEM 18" wheel with -38mm backspacing won't touch the cladding. BUT I'm running an aftermarket 18" wheel with +2 backspacing, so they rub just as much as someone running 285/60/18s on their OEM wheels.

Generally speaking, if you stick with the OEM wheels you should be able to run the 265/65/18's without much (if any) trimming. But keep in mind that our VX's were assembled by hand, so there is some variation from rig to rig. In any case, the trimming required really isn't significant.