Ouch! How are you getting on with bumpers? I also have a montecarlo estate, and had a little bump with a neighbour last May. Unfortunately it looks like the bumper was previously repaired rather crappily with filler which has cracked out, and so although getting it repaired is not too expensive, a new bumper is certainly better for the same price. For now its fine, just not quite flush, and sporting some duct tape.. black car though so at a distance its fine. I've been scouring ebay and such for a replacement with little luck, the only one i found for breaking in my spec was ofcourse in a rear end shunt. But i have come across many standard estate bumpers, as mine was damaged only on the corner, all the trims are intact, do you know anything more about how the 4 pieces you mention fit together (Bonded, studs, etc), musing about if theyre in any way transferrable to a standard bumper. Sorry, i know this is a stretch! Many thanks