Monos with the M80s are the way to go if you can swing it.
For stereo listening its tough to beat single channel amplifiers, with dedicated power supply and isolated circuitry.
Besides the dynamic headroom you'll get from the extra power, you virtually eliminate any chance of channel crosstalk. Two monoblocks are usually lighter and easier to handle than one stereo amp. Monoblocks can be placed closer to the speaker. In addition, it's better to keep speaker cables as short as possible. If you use balanced cables, there will be noise rejection along the interconnect runs to the amp.
All these benefits usually mean a better soundstage, heightened dynamics and greater resolution. However, a well designed powerful separate stereo amp will easily hold its own against a monobloc pair.
