Quandary

The$300 fee would go towards the cost of the amp if I bought it.

My 0.0002 cents, an audition that costs more than most people's (not members here) amp/speaker/etc. budget is wild. 

The absolute only way to know and be 100% sure is to hook the amps up to your system and hear it for yourself.  There's no other way.  Now, how bad do you want it?  And how much $$$ are you willing to risk in the process?  No one can answer those questions for you.  Happy listening.    

I think it likely the Pass amp would make a profound impact on your system in a very positive way. It would increase the midrange and musicality by a tremendous amount. Definitely worth the test.

Also, in general the sound character will be almost the same between the recommended amp and the demo amp… although the one recommended might be a tad less slam with a very slightly attenuated soundstage (likely to be very small difference).

Is it worth $300? I suspect it will be. I would guess that if you buy it he should refund the $300. Do you want to be sleping a 90 lb amp around. What does your system cost $30K+? The tax on my speaker wires was nearly $300.

I am really conflicted now. Evidently weak-minded. When I read the negative posts I was all set to ditch the audition. Now that I read positive remarks, I’m not so sure.
I guess I’ll never know until I listen to the Pass sound, even if it isn’t the same exact amp.  If I decide to buy it the $300 will be deducted from the cost.