I don't think anyone here will advise you not to pay for something you've bid on unless it is an obvious scam, which this is not. It is one of the most annoying things for a seller to have a non paying bidder.
The BL4000's are a very well respected speaker - personally I would pay cash on collection just to make sure you are getting exactly what is described.
Price wise - I would have wanted mint condition for that money. They are described as being very good but this is a really subjective description, this seller has sold some pretty ropey (in my opinion) items in the past & given them this description. The problem is that rating condition is extremely subjective & what one person would call "good" someone else may call "mint" & yet another person may call fair or even average. I think my opinion on good is really of a higher standard than this & some other sellers.
Having said that, as it is a "buy it now" sale it is subject to distance selling laws which means you can return them for a refund if you change your mind once you receive them no matter what the reason - so long as it is within the regulatory time and in the same packaging & condition in which they are received. You will still be stuck with postage charges though.
Chris.
The use of metaphors should be avoided like the plague. They're like a red rag to a bull to me.