First off, you'd grab at least a 100 watt/ch amp for running several zones. His Mac is likely 30 or 40 watts per ch and isn't adequate. And if by rare chance he has a Mac 275 (4 output tubes per chan) then it's nutso to use a smooth $7000 amp to run in-walls. Tell him to save it for a dedicated 2 channel room (perhaps the room where his nicest speakers are, or where he seriously listens) and add a bigger amp for the rest.