well Haunz, as im sure you well know, the simplest method is to listen. on pretty much any half decent demo board you should be able to compare two different speakers and get an idea which you prefer.
unfortunately, when dealing with high end junk, that isnt an option in edmonton, as most of the local sales people seem to think that type R alpine stuff is "the shiznit!!! for real!!1!!"

often when you mention other brands, such as DLS or LPG you are met with a blank look of confusion...sometimes they will say "oooohhh yeah, thats the new line from kenwood right??"

sorry for the continued references to alpine, its just that im more framiliar with their line than most of the other big brands, and they have four clearly defined performance levels.