Well, I've spent a frustrating day trying to isolate a loud bump that comes from the right rear area of the car. Got it up on the lift 3 times and checked practically every fastener in the rear suspension and the rear end. Even moved the rear brace down with some spacers to get it farther away from the tail pipe. Found that the battery was not fastened securely enough and could move a bit so went to great lengths to secure it as well as possible... All for naught, I still have the noise/bump when I go over rough patches of road or irregularities. It's really hard to evaluate the coilovers for their ride when that clunk/bang/bump happens.
So far everyone who's driven the car was very impressed with the coilovers even though the noise happened during the rough bumps on the road. I would appreciate any ideas about what the noise could be and how to eliminate it. It sounds as though some part of the car bumps hard against the body/frame in the right rear part of the trunk (right where the battery is). We spent quite some time rechecking every mounting point of the coilovers as well as the obvious mounting points of the rear end. I also emptied the trunk completely and secured everything in there that I could see as well as possible... Oh yeah, as the suspension settled a bit, I raised the car about 1/2" in all corners.