In Need of an Amplifier

I have the following:

5.2.2

3 - Sierra-2's Up Front
2 - Luna's Out Back
2 - PSB Imagine Atmos
2 - Rythmik FVX15's

Denon AVR-X3300

The Denon is currently running the speakers just OK. Having never owned a true amplifier, only AVR's, I feel that I am probably missing something or not getting the Sierra's/Luna's full potential.

The Denon AVR-X3300 has pre-outs, therefore I would just like to add a 7 channel amplifier to run all speakers. Here's what I'm looking at:

Outlaw 7140 140WX7 8 Ohm (least expensive)
Made by ATI
Probably has more than enough power for my needs
Only 53lbs (my current shelf should be able to hold it)

Monolith 7 Channel 200WX7 8 Ohm
Very Heavy (90+ lbs) Not sure where to put it at that weight
Cheap for the power and made by ATI

Emotiva XPA Gen 3 7 Channel 200WX7 8 Ohm(most expensive)
Plenty of power
Dynamic power, so will have 300W for stereo use
Expensive for more power I may not need.

Just to understand speaker power ratings better...If the recommended max continuous power ratings for the Sierras and Lunas is 150W (PSB's are 80W Max), it doesn't mean I can't use the Monolith or Emotiva...It just means I have more headroom if I crank them, but only play them to a level where 150W max will be needed?

I don't think I will ever really turn it up too high. I usually stay at or below -15db (=65 on Denon) right now for movies since I don't want to hurt the speakers with the lowly powered X3300 running all 7 channels. I would like to go a tad higher once in a while, hence the need of an amplifier.

So, would the added expense of the Monolith or Emotiva be worth it for the added power I may or may not need? I know there are probably sound quality differences, but may not be noticeable to my untrained ear...

Thanks for reading, and providing any feedback you may have!

You'll be fine with any of those I'm pretty sure. Lots of people here are fans of Emotiva and the Monolith/ATI amps. I'd probably go with the Monolith or Outlaw model since the Gen 3 Emotiva amps are so expensive and use switching power supplies now, even if they are really big fancy ones. I'd probably go with the Outlaw one just because it's an unbalanced design and your receiver has unbalanced preouts, The Outlaw 7140 has balanced inputs, but they're just summed with an IC to single ended. Seems pretty perfect for your use to me. I don't think you'd really notice much of a difference between 140 and 200 watts. Sierra speakers are pretty easy to drive. I don't have to push my XPA-5 Gen 2 hardly at all to send my Towers to ear-bleeding, epic levels. I haven't heard my Towers with any other amps, though. Curtis has more experience and may chime in.

As an aside, I think what makes the Monolith/ATI amp so heavy is the fact that it has not one, but two very large toroidal power supplies and a very sturdy chassis, plus the amp modules have huge heatsinks on them. It is a very robust design, a monolith indeed.

I agree with sludgeorge also - I'd go with the Outlaw also.

I'm using an Emotiva UPA-7 with MRX510 to drive my Sierra 2's (LCR) + surrounds - no problems. It's similar in power rating to the Outlaw.

You could also get a nice 2ch amp for stereo pair, and use the denon for surrounds. Optionally adding more dedicated amps as you go.