Edpowers
As a mono block devotee I usually would agree with their use, BUT in this case having heard the 500's on the 100's, the sound was simply too tipped up and edgy when the volume was raised.
There are distinct diffs in the sound between the 402 & 602, apart from the obvious better control the bigger amp provides, there was more weight in the tones and voices were more immediate.
I came very close to buying the 602 back then for my BWs. In the end however given $$$, and again, I could have lived very well with that 402. That and the fact the 602 was about my limit for amp hoisting and shifting about... it's well over 140 lbs as I recall... so there's that too.
The 402 is absolutely a very good amp. No question. At this point it's more a matter of degrees now than distinct night and day desparities.
the notes above regarding a possible forthcoming speaker move up should now be addressed and either amp, 402; 602; or monos as well as expense ought be given due consideration before diving on into one of these solutions.