I got the bumper back from the body shop today and installed it. The smoothie rear bumper looks good and by removing the bumperettes (7.5 lbs each), rubber molding strips (0.5 lb each) and converting from the US shock absorber bumper struts (4.5 lbs each) to the Euro hollow tube bumper struts (1 lb 9.5 oz each) I trimmed 21.8 lbs off the tail end of the car.
Bumper mount as installed:
Original rear bumper:
Smoothie rear bumper:
Thank you Pelican Parts forum for the inspiration!