The 6-ch. amp I was considering had 4x55W and 2x110W
Wow, thats quite an amp, buy the looks of those numbers that would be more than effective for running your desired setup.
Or with the 5-channel, the fifth channel I would assume is a mono channel, so basicly the lefty-righty sounds get squished into one, good for subs. However, depending on the type of music you listen to, often the bassline or the low end frequencies are in stereo (lefty or righty channel), thus the need for stereo-centric subs are in order (dont take this as the law, as a mono sub can differentiat and play these anyways, regardless of channel)

Ask your installer, and let him give you a good reason to go with 5channel vs 6channel, then call a couple of other shops and get their opinion, then take the most popular opinion and run with that.

I am certain there is an audiophile greater than I, who can explain better what I am trying to convey.

Smoker_Man
#080000449 MkII - 36Gb Blue