Advice on AV Receiver versus Separates

One further note on bi amping. IMHO:

Bi amping has benefits. Without doubt, it certainly has theoretical benefits - an active x-over ahead of the power amps will generally produce better distortion and phase performance. Further, offloading deep bass to a subwoofer will likely increase any system's max clean SPL capability, but....

You're already bi amping this system when you add subwoofers. By bi amping the mains, you're effectively tri amping the system. While there may well be additional benefits to this approach, I'd agree that this is a low return on incremental spending.

Per Bob,

I assumed the OP would use the bass management in his pre-pro, so he will almost surely get the benefits of bi-amping there. (No REL style, high level crossover set-up to argue about in this case).

My comment re: low return on incremental spending was reflective of the OP's stated intention to add a second power amp to his system to "bi-amp" the main speakers. In all likelihood, that would fail to achieve most of the benefits provided by bi-amping, anyway, since the crossover remains in the wrong place. As to the superior cost benefit tradeoff for the proper biamp arrangement in most powered speakers, I'd defer to those who know the market better. That includes lots of folks out there; Bob among them, for sure.

Marty