why would the glass crack?
You can take a full size gm body off the frame, put it on jack stands and all the doors/ trunk still open and close fine.
Drag cars run solid motor mounts, solid tranny mounts, sepherical eyelids for shocks and control arms....
Even unibody cars that recieve full frames underneath (tube chassis or 2x3) are essentially doing the same thing.
(not blowing off your opinion, just legit asking why that would potentially happen, not saying your right or wrong)