Need Advice on Amp Audition at a Dealers

One problem I can see with your idea is that you need to think of the speaker and amp as essentially one component.  Unless the dealer has the same speakers as you do, you will be hearing how your and another amp interact with the speakers they're hooked up to; they may not work the same way with your speakers.  If he has the same speakers as you, then your idea will work well

What amps are we talking about ? Maybe the answer is very obvious even without auditioning side by side. I wouldn't do it with my Redgum and Gryphon or Lamm - Redgum would lose big time with any speakers.

What amp are you currently using ? What amps are you looking at ?

A home audition is best.  Ask the dealer to send out one of his techs to set it up for you.  If you need it for a few days, you'll have to pay for the tech to come back, but the cost won't be that bad.

The advantage of letting someone else set it up is that you can concentrate on the performance, letting the other guy handle the technical details.  We are all capable of doing it ourselves, but in this type of situation allow yourself the luxury of being able to focus on the sound quality and system synergy.  It will be fun and rewarding.  If you end up buying the amp, you'll probably be able to work out a deal.  But the service will be worth every penny!

Oops... just read your message and realized the dealer is hours away.  Might not be practical, you might have to do it yourself if the dealer is cool with that (they usually are once you throw down your plastic).