ok, gotcha. just looked at the site and paid attention this time and see the size difference. i thought the only difference was the amount of travel, and the structure only changed once you made the leap to an MTN version fork.yep.
the 7.5 is single damper dual bolt crowns.
the 8.5 "MT" is triple bolt lowers, standard uppers, and thicker/larger uppers around the lower crown. Should make for a hell of a stiff fork, but I'm not convinced that the twisting isn't related to crown design rather than clamping force (ie no need for three bolts).
The damper has nothing to do with twisting, and I'm fairly certain two dampers are not necessary, especially with the oil volume and damper design of the huge-o fork.
I think the extra half inch of travel, from what somebody suggested earlier, is a measured amount of negative travel, that other manf. already include, but Avy does not...correct me if I'm wrong.