[krug300]

Doesn't make a difference, the additional rear glass is there anyway, remove the headliner and you will see through the rearmost glass.........cut a hole in the rear of the headliner, place a piece of trim around it and you have a rear "sunroof" minus the shade if there is one in the OEM installations. No logic to it.
To repeat myself, I think shattered Ultraviews must be because of a manufacturing defect. My SRX fell off a towtruck when it jacknifed, ended up upside down after sliding(on its front part of the roof/glass) for a good 20 feet on tarmac. The glass was severely scratched on its "leading edge", but did not break.