Intermittant problem in W210 with Bose
 

When I hit a bump I lose some of my speakers, another bump and they come back. Obviously I have a loose connection somewhere, but where should I start looking if it affects more than one speaker? The back of the head unit (Alpine) or at the amps which are under the back seat (I think)? Somewhere else? Thanks in advance.

I would start looking at the obvious places - at the speaker terminal connections. Can you isolate which speaker(s) is cutting out? Start there and check connections at the speaker itself.