How do I pay?

I am in negotiations to purchase a pair of $4000 speakers. The seller wants a cashier check. He has no feedback on Usaudio sales. He does not accept PayPal. How do I pay and protect myself?
I've done something similar to this 3 times but all with respected dealers, i had to send a bank wire transfer because i live in Canada and all the dealers were in California. once to Robert Lee (Acoustic Zen) for  Absolute speaker and interconnect cables, once to Scott Walker (Scott Walker Audio) Synergistic Research powercell10 UEF power conditioner and once to David Weinhart (Weinhart Design) a pair of REL G1 subs, these were all expensive transactions and they all went smoothly and everything arrived as if it was brand new (actually cables were) but i would have never in a million years done this with a private party sale.
the problem with buying used is often between shipping, PayPal and sometimes listing fees there’s no incentive. Personally if the value is enough to include PayPal fees offer it otherwise wait for a local sale.