Are we just talking bi-wire(running two wires out of one side of the amp and into the cross over of the speaker) or are we talking Bi-amping(using a seperate amp for Hi, Mids, Lows and an external, usually active, cross over)?
If the first, and you heard a difference then great. Not sure how it could make a difference but if you noticed it who am I to say you didn't.
Bi-wiring, to me, is on par with "Monster Cables". Looks good but no real benefit.
Again, just my opinion.