dtrandall, well, most peoples' systems are "happy" at lower volume. Doesn't take extreme sound for that comfortable sound.
It's not assured from your descriptions that the issue is not the speakers. If you are hankering for a more voluminous sound than those speakers can provide, it won't matter what amp you put on them, they'll be quite limited in comparison to some other designs. Something to chew on.
See, you thought it was a simple, "Pick the right amp," question. Nope; it's much more complex than that. However, accept the challenge of finding your dream system and have fun with it. I recommend you first familiarize yourself with the expected performance outcomes of different speakers and genres of speakers. In the end you could pick even an entirely different genre of speaker. It's a wide open field of discovery.
Get thee to shops (when open again!) to hear some stuff, and for sure try to attend a show - eventually. Until then, keep reading, keep exploring, keep asking... LOT's to learn and consider. You won't have an easy time picking, and when you do you'll be tempted to second guess your decision. Perhaps you should, perhaps you shouldn't. There is no magical template. Building your dream system IS a lot of trial and error over time, and no one can magically make it appear for you, unless you simply accept their recommendation, and in that case you still have no assurance you did the best. :)
The more serious you are about this, the more gear you have to handle, if your goal is to gain assurance you are moving upward toward a highly developed rig. You pick how hard you want to push on that. :)
I'm going to be candid, blunt in one respect, in regards to assessment of your system/speakers. I mean NO disrespect, this is for analysis of your desires. The cabinets are small and light, the volume on cabinet and driver size is quite limited. I had a set of Kirksaeter Silverline speakers similar; nice, but lots of upscale characteristics to gain if I wanted to move up. Imo, some of the messier sound you hear is due to the cabinet when volume elevated, and I suspect the bass gets messy as a result.
I suspect your speakers are the better upgrade. That is not to suggest you could not see some improvement with a different amp; of course you could. However, if you want to vastly change the experience, you should seek different speakers. That would be a sea change in performance.
You mentioned "low end grunt"; I wonder if you are wanting more impact, more presence. Those speakers cannot give it to you in spades. the bass performance on those is closer to a bookshelf than a big tower speaker. Imo, begin looking for different speakers, not a different amp. A move to an Adcom or similar will be more lateral than upward. Different speakers can blow this performance out of the water. If you don't have enough money, save for it. It will be most worthwhile. That's not to say the Outlaw amp should not be upgraded eventually, but imo speakers are the direction to go. :)
I have zero interest in debating my recommendations.
