Better check around about amibay before you take that plunge. Apparently bad things can happen out of the blue.
Quite to the contrary, Amibay takes greater pains to protect its members than any site I've seen. I'll second the recommendation for it, but make sure you actually read the buying & selling rules, they do enforce them.
Anyway, please split it. I know it's more work, but nothing's more annoying than seeing a system you'd be interested in buying that the seller won't give you because they only want to move the whole lot.