First some pictures:

I took my Smart to the dealer this morning for an estimate.
They said the damage to the bumper didn't look severe. But the real problem is that the tail-gate was forced upwards about 1". In doing so, it bent the two bracket-guides on each side. Those bracket-guides are attached to the metal, possibly the tridion-cell, and may have damaged that. That is where the real damage might be. They won't know for sure until they disassemble the entire rear-end. As a result the tailgate won't close properly.
The initial estimate was about $2,500, but with a big cautionary note that when disassembly starts, it could easily go up to $4,500.
Now, a question for the group: The other driver is a little anxious to settle this outside insurance, so as not to affect his business. I'm not opposed to doing this, but I want to be sure I'm protected. Has anyone done repairs outside insurance before? What're the issues to be aware of before? Or is it just better for me to insist on involving insurance companies? All advice is welcome.
-abelenky