Wait, maybe I'm having a dumb moment here lol, but what do you mean by negate the benefit of the iS mount? Just as in add a little additional more, possibly annoying NVH? Or just make the mount no more beneficial than a standard mount?
I could be way off here, but I was under the influence that the only difference between the regular and iS mount was that either the viscous fluid was a bit thicker (like 40w vs 30w oil) or the rubber holding it in was a bit thicker, thus keeping the ride feel the same except when compressed quickly/further like under acceleration or turning. I've never seen one up close due to the cost so I'm not sure if I'm way off base here, but if it is how I imagine it then I would think there'd be no increase in NVH (vs a standard OE mount) but you should still get that extra bit of stiffness from the plate still since it's really only felt when load is put on the mount, not at all times.
If only Rob Beck was here to tell us how these VTT products would work!