What does the plus sign indicate on a pair of PMC DB1+s? I'm assuming the DB1i is the newest version. Is the DB1+ a special version of the old DB1? I'm asking because there's a pair of DB1+s on ebay, going for 450 quid at the moment. I've got serious reservations about buying secondhand speakers on ebay, for all the obvious reasons, but does anyone have any comments as to whether or not this is a bargain. I don't expect the price to stay at 450, of course. Neither would I expect to win a bidding war. Just asking out of interest, really.