Benchmark AHB2 in Mono Block Configuration

Hi:

I've owned the Benchmark ABH2 Amp for a few years but am now considering one two alternative upgrade paths:

A New Amp or adding a second AHB2. If I purchase a new amp so far I like the Bryston 3BCubed which is a dual mono design with 200 watts into 8 ohms or possibly the 4BCubed at 300 watts. In either case this is more power than the single ABH2 at 100 watts into 8 ohms. However adding a second ABH2 increases the power per channel to 380 watts .

So much for raw power. What about overall sound quality? The Bryston 3BCubed got an excellent review on Absolute Sound as an amp that would require significantly more $$ to better. Another review I read easily preferred the Bryston 43Cubed (300 watts per channel) over the ABH2.

I'm in the process of completely upgrading my system after several years of the same components. I will shortly have:

An Aurender N20 Streamer into an MSB Discrete DAC with dual power supplies feeding the single ABH2 which drives my Harbeth C7es-XD speakers.

Everything will be new except the older ABH2. Hence the consideration of an amp upgrade.

Now Benchmark will tell you that adding a second ABH2 is only needed when the single amp clips. Other than that there is no sonic benefit to adding a second. I Ffnd that hard to believe. I would think having a second would offer improved soundstage, separation and possibly better performance from the speakers. So my question is:

Have any of you added a second ABH2 and if so what were the overall sonic benefits if any? Also any opinion or experience on the Brystons vs the Benchmark? Or any suggestions of a better upgrade path would be welcomed.