McIntosh MC152 vs MC162

MC162 is an older amp, it does not have autformers, lightweight, at half the weight of MC152.
MC152 is a current amp with autoformers, it is rated at 150W per channel but will deliver 200W. The new price is $4500, used ones, B rated, at Audio classics are listed at $3500 give and take.

No contest between the two, the MC152 wins hands down.

I would agree with the others who recommend the MC152.  Not only does it have the autoformers, it have both single ended and XLR inputs, more up to date circuitry (I believe the new generation output transistors), and would most-likely have much less mileage on it!

...not to mention the 152 has plenty of headroom. Right up there with the best of the McIntosh amps. I have one in my office rig and fully enjoy the sound. 152/C47 with 805 d3’s. Hard combo to beat in a small space. 

What are your thoughts on using the MC162 to power surround speakers in a McIntosh system?

I have owned a 2125, 7100, 7200, 122, 202, 162, 452, and 152.  The 152 is the best I’ve had by far, better than the 452 even.  They really lucked out with its circuit.  The 162 is good for the money but a bit grainy and with a constricted soundstage compared to the newer models.  I suggest a 152 if you don’t need ridiculous amounts of power.