EDIT: Tony of Powerinspired kindly called me back and the gist of what he said was that adding a Quantum or other filtering/purifying device in the chain would not cause any problems as such. It may just be that the noticeable effect of the filter/purifier may be reduced because of the improvements brought by the AG itself, but that it really depends on the nature of the filter/purifier and, as we know, this varies from one product to another. I haven't finished trying all the possible configurations with my particular system with Vertex tagas and Quantum in or out of the system (as it takes a long time and is a bit of a fag swapping cables around behind my system) but what I can say is that for a relatively small sum (compared to what we pay for a couple of cables and other system gizmos) it's worth trying one of these out particularly for someone who has no existing mains conditioning/filtering/purifying - it's very quiet -my fans are turned down to minimum without any problem- and it's plug in and play item. As someone else has mentioned on this thread you don't need the battery option just the AG itself.
Tony tells me they are flying out of the door at the moment (salesman as he is) and maybe Tony can be persuaded to extend the generous discount - hint hint - to encourage others to give it a go.