I can't find the original roadfly post, but according to the repost to a quote in public folder at work:

"Just got back from my dealer (Seattle BMW) - anyway, this customer comes in - looks at this '03 SMG - wants a test drive - my salesguy goes with - they go on a regular test route in Seattle with a few twists in the road - anyway, the salesman says this dude goes into a tight corner at over 40, then brakes, tries to correct, DSC cuts in, then they hit wet leaves - driver loses control completely - car goes down a 30 ft decline and rolls. Both, the driver and salesguy came out fine - note the roll bars ejected from the rear headrests..."
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And then some observations:

• The roll over protection bars are well above the level of the passenger’s head.
• The roll over protection bars feel flimsy to the touch and rattle left to right and fwd to back.
• However, the car rolled over on to them and rested there, so looks are likely deceiving in this case
• The roll over protection bars punched through the soft top, which was of course destroyed in the roll over
• The A pillars are completely intact, straight, and rigid
• Windshield glass was not released in to the cabin
• Side windows were fragmented and the pieces had randomly fallen away. Jean-Marie says the side windows are designed to do this for rescue
• The bumpers appear to be made of a carbon-fiber-esque material
• There was significant damage to the right rear panel. Very odd that side airbags did not deploy even though the impact was rear of the door.
• Some cars’ side airbags deploy automatically in a roll over, not the case here.
• Despite significant impact in the right rear, there was no cockpit intrusion
• Passenger compartment was maintained extremely well
• Jean-Marie says that the seat belt pre-tensioners were activated and were holding the passengers upside down in the car after the car came to a rest