Along these same lines.... anyone know what (if any) chains would be considered ok on the Model X (20" wheels)? We already have a set of these Security Chain Company ZT735 chains that we got for my wife's Highlander hybrid, so I'm curious if something along those same lines would work just in case we wanted to take our X to Tahoe. (Although if the weather is bad enough to require chains on an AWD, perhaps we'd only take the Highlander anyway).
And answering my own question... turns out the ZT735's are also supposed to fit 275/45-R20 and 265/45-R20 size tires that are on the X so we may be fine already. Presumably you'd want to kick the suspension height all the way up and disable automatic lowering.