Not Sure if This is the Correct Place in the Forum, But...How Would YOU Go About This

[IntelliVolume]

I wasn't sure if this was the proper place in the forum to ask this query, as it could probably fit in the Receivers, Speakers or even general audio setup areas, but my apologies if it wasn't...

Here's what I'd like to know from anyone who's had any experience with power amps (specifically connected to AVRs): As we get ready to move into the UHD/4K realm, I am considering upgrades (of course, the 4K display would be first, then Oppo's 203 UHD player) with one of them being a new AVR that can handle the Atmos and DTS:X "enhanced" codecs. My current AVR, an Onkyo 605 that has been an absolute beast since day one and still soldiers on with ZERO problems, does not have preamp outputs, and I'd be looking to feed my front speakers (monstrous Polk RTi12 towers) with some external amplification...

The question is, I don't really know the best way to go about this; I know the new AVR needs preouts, of course, to take advantage of the power amp hookup, but would it be best to get a three-channel amp (say, like an Emotiva) to power the RTi12s and my center, or a two-channel model just to power the RTi12s? The speakers can take 500 watts RMS each (though of course I don't need to feed them absolute max power) so I'm looking to get some serious juice to them.

I figured I would get a new receiver and use its surround channel amps to power my surrounds, while letting a big power amp take care of the front...would this make sense, or should I just look into a five or seven-channel amp model and skip the receiver's amps altogether? Always seemed to be a "waste" of a receiver's amplifiers by "ignoring" them and using it as a standalone processor, but...

So, would it make sense to power all three of my front stage speakers with an amp, or just drive the RTi12s with a two-channel model, leaving the center and surrounds to be driven by a new receiver?

Also -- being that I'd be moving from Onkyo's "rated" 90 watts-per-channel spec on my current AVR to bigger numbers on an external amp, what kind of power increase do I need to look at here? I understand that simply doubling the stated wattage doesn't yield "double" the power, so what kind of jump would I need to make in order to really perceive an output change at least into my RTi12 mains?

I suppose what I'm asking is, if my AVR is "rated" at 90 watts-per-channel (not getting into what I'm ACTUALLY getting with the receiver), how much power in an amp -- and which models -- do I need to be looking at to really get these RTi12s to sing? Would an Emotiva make a difference, or do I need to look at something much, much bigger? How about Emotiva models that can be "bridged" to produce more power?