The 150 muffled? I have never had this feeling, nor heard anyone else ever refer to one as muffled, possible problem with it? Anyway, 3 M80s across the front is the way I would go. I ran an M60 with the M80s as a center till I had to send the M60s back and that was the best front soundstage I have heard, nothing like a FULL range speaker for a center to really liven things up, I would highly recommend going this route.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70