For speakers, I picked up B&W 805D3 tabletops with stands. 88 dbSPL sensitivity, 8 ohm. They recommend 50-120W @ Ohm for the amp power on their site.
... For the MA5300, I’m concerned that there isn’t enough headroom. If I even get close to the 94W peak, it means that I’m pushing the amp to the max, so I’d probably be operating in an area of reduced sonic performance since it’s being stressed.
More significantly, IMO, you would be pushing **the speakers** to near the max. Note that B&W’s recommendation for amplifier power, stated fully, is:
50W - 120W into 8Ω on unclipped programme
Meaning that its ability to handle **continuous** power (which is how the amplifiers are rated) is certainly much less than 120 watts, at least if the speaker is to provide reasonably undistorted sonics. Which also seems consistent with the fact that it is a small (28 pound) two-way speaker having a 6.5 inch woofer.
Finally, there are undoubtedly a great many design differences contributing to sonic differences between the three McIntosh amplifiers you are considering. I would not let your decision be dominated by the presence or absence of autoformers, or by any small handful of design characteristics. I would start by researching what amplifiers others use with the same or similar speakers, and what speakers others use with these particular amplifiers.
Good luck. Regards,