Just to throw this out there, you may want to consider that Denon, if you think there might be an upgrade to M80s or something of that nature in the future, as the Denons have proven to drive the 4ohm load with out problems. I currently have about a 3 ohm load as my center channel and my 1804 hasn't shown any ill effects.

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