Need Advice on Amp Audition at a Dealers

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).

Try an Icon Stereo 30 SE from Music Direct.  If you don't like it, they have a 60 day return policy.  I have a hunch they will pair up nicely with your speakers, which are just crying for Class A single ended power. You also may end up not needing your preamp (the 30 SE has a built-in passive pre).