Krell showcase vs older models

I'm in the market for another amp. I just need it to drive the "height" channels for DTS X. Some "expert" told me that the Krell Showcase line isn't very good -- is this true? I've searched some older threads here and saw that general consensus is that Krell outperforms Parasound. However, is that still the case if I am to compare the Showcase 5 to the Halo A51 which has received many phrase? 

My system:
Front -- Martin Logan Aeon II
Center -- B&W HTM1
Side -- Dynaudio (custom made)
Back -- Dynaudio Contour 1.3
heights -- Dynaudio audience 42W 
Processor: Rotel RSP-1576

The thing is, I personally don't think it takes that much power driving those audience 42s. I have the Halo A51 driving the MLs and the center already. I can pick up a B&K Ref 7 channel amp for fairly cheap. Would that do the job? 

Thanks,
Ryan