My VP-180 is about 3 feet higher than my M60's... So my tweeters are not on the same plane.. My 180 is angled down, even though the tweeters are not on the same plane everything in my system blends quite well...

Doesn't Audyssey make time corrections when configuring all of the speakers, so that all of the sound waves arrive at the mic at the same time? I don't have Audyssey so i have no clue...