buying used speakers

Thanks to all for for input. Let me be a little less general. I am seriously considering buying a pair of speakers listed for $4000 on this site. List price for the speakers is $7200, and checking around this is what they sell for. They are nine months old and said to be in absolute perfect condition. There is no feedback listed on this seller. If I do this I will use an escrow service so I can inspect speakers before the seller gets paid. Seller will send me close up photos and original sales slip proving age and ownership. I have had great luck buying and selling on this site so far, but have had no transactions this large. Am I insane?

Thanks Carl and Swampwalker for the input. I just wanted to bounce this off someone before I did this. I have spoken to the seller on the phone a few times. He told me where he bought them-so I called the dealer and he confirmed the sale. The photos look good so I am (excuse the pun) committed. BTW they are Proac 3.8's

Speakers arrived yesterday. They are perfect. The cherry veneer even matches my built in bookcases which helps with WAF. Bass is deep and tight. Soundstage is wide and open. Voices have chest and throat. I can even listen to all those bad recordings made by people on drugs for people on drugs in the late sixties and early seventies without ear bleed. I think I will have these speakers for a long time. I used I-escrow for the transaction. You can specify the length of time you want to inspect the merchandise before notifing I-escrow to pay seller, or if you want to ship it back. Takes a lot of the risk of buying used gear site unseen, and I will use it in the future for any substantial purchases. My winter project to design a decent room for these babys.