Now that this frame is sitting in my garage, I had the opportunity to look at it from all sides.

Just to be clear, my understanding is that this frame is one single piece, there is no repair option to any other part than to the front, which may be cut off right in front of the windshield and replaced with newly welded parts.

Now if we look at the other parts of the frame (other than our beloved strut towers that is), what can we see?

Almost any impact that goes beyond a simple fender bender will hit the frame. Just think about somebody sleeping at a traffic light and kissing your rear side (of the car of course).
Look at the point where your trunk lid ends, measure the distance to the end of the car. Right in between, there is still a part of the frame. So any deformation that is more than 3 or 4 inches will inevitably hit the frame and crunch it IMHO.

Same is true for side impacts.

Now, it is not surprising for me that there are frame parts in areas that could be hit in case of an accident. However, in "normal" cars there is a chance to cut and replace frame portions in most cases.
I can't see any of this working on the Z8.

More and more I reach the conclusion that the car was built with a museum in mind, but not for regular driving. Oh, and btw, if somebody hits your rear, this may happen at times when your not driving in a spirited fashion on bad surfaces.

I hope somebody can point out that I'm wrong with my assumption. If not, it's another point for me to have a spare frame.