Each state has its guidelines for what gets 'unrebuildable' or salvage. Here in NC a title with the unrebuildable branding will not be inspected for road worthiness and titled. I bought a theft recovery years ago and NC said it was unsafe although never hit!
It was the $$$ that put it over the max but only if you went to the MB dealer for the parts, not salvage parts.

Bought a 400E last month that I looked at before it went to the auction. No frame damage as an oak limb fell on the roof...and
all doors opened fine...drove it home on a dlr. tag! There are forms to fill out specifying what and where you bought the parts to repair the car. This can enable you to get the 'salvage' branding off the title.
I also take pictures before, during and after repair to show a buyer the extent of damage and let the buyer know all the paticulars. Being honest helps, but then there are those that XXX! So watch out and do a carfax check.

Tobias MB
4 MBs now