nice speakers!
low efficiency 87-88 and 6 ohm dipping to 3 ohm, that is a combo that needs the right choice. Your friend's unit, 125 wpc at 4 ohms seems to fit. Will he let you hear it with your speakers?
Nothing I own is right for that, and past McIntosh 300wpc was amp, not integrated.
I'm interested to see what people recommend and you choose, best of luck.