Does anybody have any info regarding whether having a full size spare would negate or effect the rear crumple zone on the MDX since the normal spare is the smaller donut?
No info, and I'd bet money you won't find anything other than opinions...(who'd test it??)
Since the spare is outside the cabin envelope I'd venture the impact to be minor. Plus the spare is not structurally attached to the vehicle, but rather clamped in the middle.
In any event, I'd not want my kids in the rear seat no matter what spare tire was underneath...