Good question! (Wish I had an answer!). The only thing I can think of is that the 4x4 is slightly longer. Maybe this has something to do with the placement of the sunroof? I noticed that there is a ridge along the interior roof just under the headliner. This might interfere with the placement of a sunroof on a 2wd E. Not sure. I would like to have an after-market sunroof installed. Does anyone know if that's possible? (You first! ). Smiles!
Honda stats show identical measurements for wheelbase, width, length, and track for all models of the Element. The ridge in the ceiling of the 2wd is also in the ceiling of the 4wd and is more pronounced as it frames the front edge of the skylight.
The 4X4 IS slightly longer than the 2WD model (according to the specifications manual). Sorry to disagree but this is correct information. I am still not sure it has anything to do with the lack of sunroof on the 2wd models though??