Surround vs Stereo Amp for Surrounds
 

With more and more channels becoming the norm for HT applications, I need to upgrade my theatre surround amplification.

I currently have MC152's powering my main side and rear surrounds and an MC205 for all height channels. Even under reference volume the MC152 have never hit powergaurd driving pretty hefty B&W CWM8.3D 3-way in-walls! But wondering if i am missing anything from more power.

I am wondering on simplifying my amplification, and hopefully improving it by getting two MC255 surround amps.

Do you think the new MC255/MC257 amps @250w would be a worthy upgrade over the stereo MC152 that are 150w? The MC152 has Mac's autoformers and a better S/N ratio so wondering if that still is the better choice.

Would you run the MC152's as heights or MC255?

I am a firm believer in output transformers (or autoformers in McIntosh speak). They give better control over the speakers (as long as the proper terminals are use for the speakers).
To me it is significant that McIntosh built some direct-coupled devices early in the transistor startup, but rather quickly went back to autoformers - especially on their higher end pieces.
Now - when you start putting 5.1 or 7.1 amps all on one chassis, the problem becomes the weight and cost of all of those transformers.
Personally, I like stereo units with autoformers run in mono mode for each channel. I have two MC2500s, four MC2255s, and two MC2205s, all running in mono mode. The only problem is remembering which units are running which speakers so they are kept in balance.
Thanks,
Jim