As for the buzzing, is there anything at all loose inside the cabinet which could be causing this? There is also the chance that the drive coil hasn't been centred correctly when refoamed but I would also expect to hear distortion even at lower volumes if this was the case.
I know it is extra work but you should try swapping the drivers over and see if the problem follows this speaker or if it exists in the cabinet somewhere........ Actually on this basis it would also be worth simply switching the cables on the amp output first and see if the problem switches speakers to rule out the amplifier.
Chris.
The use of metaphors should be avoided like the plague. They're like a red rag to a bull to me.