The E36 M3 style mirrors are a nice touch too.
Years ago when people were working on converting the E30/E36 chassis to a true coilover setup in the rear for race use, the sheetmetal was a problem as it would often warp or tear from the extra load- it was not designed to tolerate the force of a spring mounted at this location.
I wonder if converting to a coilover application in the rear of the car would really be as simple as changing the damper/spring to that design. Judging from the photos it seems that it may be more complex than that, as it seems that the upper mounting area is reinforced by the roll cage on this car. I'm not sure though.