I hope you have history with the seller and have verified the authenticity of his items at the very least.
IMHO this sounds like a risky venture for sure. So much could go wrong there...
If I was going to spend that much on high end audio I would want to hear the items in a showroom setting and make sure I was dealing with a licensed distributor. If you purchase from other then a licensed distributor in most cases any factory warranties will be voided BTW.
As previously stated it is odd the seller would not have a payment processor in place if selling in that value range.