As impractical as it may sound, if you are road-tripping, take your amp with you. Synergy matters and generally a retailer is going to match up their speakers with electronics that work with those speakers. So unless your planning on buying the dealer's electronics as well, bring the amp that will actually be driving the speakers.
And, if you have some big-a*s SUV, take your listening room with you as well. Location, location, location....