My 2 cents...
Using a power conditioner with amps may sound good, but given how power draw from transients might limit how the amp is able to produce an accurate reproduction of said power draw.
Utilizing a directly wired circuit from the mains would be, in my opinion, the best way to connect your amps. Adding a whole house surge protector would give you peace of mind should a power surge occur.
@overthemoon , +1. Contacting McIntosh would probably be the best way to get what they consider the best path.
Bob