You have a well balanced system: high current, stable amp, a good source, and a difficult acoustical challenge. Your challenge will be determining placement for proper sound reproduction. The subwoofer should be added to a music system (as opposed to home theater) to improve an already good pair of speakers. Either listed will do a wonderful job, with higher marks for the M80.
Just curious, is the Rega green? What arm and cartridge are you using? I have long had a great fondness for this table with certain arms and pickups!