Trying to find an amp that matches my tastes (aka death metal)

Id stick with solid state if you are trying to stay away from warmth. I have a First watt J2 and that paired with the Zu DW is awesome!( also have the zu DW's as a 2nd setup)

Non of the gear in your system has a way of knowing what music you are playing, only you know !

Given that if you go for the warm side of neutral then you will be robbing some of the feeling of Death Metal, it will sound rather boring, exactly opposite of what this type of music should be!. Conversely if your system is on the bright side of neutural then your music will tend to screech at you when no screech was intended and that will bring with it fatigue (yes you can have fatigue even with death metal).

With this type of music I think its even more important to have a very neutral sounding system specially at higher volumes (which I presume is what you are listing at most of the time)

I have nothing against tone control or equalizers provided they are properly designed. such units of course exist but are very costly and you probably have to look into Pro Audio to find a decent one.

But then the issue may become you spending more time adjusting things than actually listening to the music.

IMO it’s better to have a very flat system and just listen to the way the engineer has mixed the tracks. If you don’t like the way a particular album sounds you may listen to it less. Unfortunately you may find a lot of recordings very compressed, but that’s the nature of this type of music.

Hey KCDD, 
I am not familiar with the electronics you are have now with your Omens, but I am very familiar with where you’re coming from. I own many pairs of speakers and lot of Zu’s. And I listen to a lot of metal. My system changes frequently but about half the time, I find that most of my metal music is unlistenable. Most of it is just really poorly recorded and some gear just really showcases that. 

If I were you, my next step would be to try the Schiit gear with the Omens. The Aegir was compared to the First Watt SIT3 in a Stereophile review and he called the Aegir about 80% of the SIT3 (paraphrasing). I don’t think you need the mono blocks though cause the Omens can get insanely loud with little effort. I heard the Omen DW’s at the most recent CapFest and Zu played them so loud, the walls of the humongous conference room were shaking. And then I asked Sean, “about how many watts you think are going into the speakers now?” He said probably 30. My phone SPL meter said 120 dB and I was 15 feet away. And it was still really clean sounding. You don’t need a lot of power to get those going. 

I understand what a lot of the other responses you were getting, saying that the gear doesn’t care what genre you play. That’s true. But different genres vary in recording quality. And most metal is recorded piss poor unfortunately. So it does matter what you pair with your speakers. I say upgrade the gear but keep the speakers for now. I’ve gone through a lot of gear and it’s hard to beat the Omen DW’s for anywhere close to that money. 

And don’t know if you know this band, but In This Moment is great. But the recordings suck. I often use their music (especially the first 3 albums) to gauge where my system is going in terms of harshness. On certain systems, the high frequencies are really really harsh and the dynamic compression is really fatiguing. If you listen to their music on your current system and it doesn’t bother you, than that’s fine. But if it does, you might have to move towards a more forgiving direction for your system. 

I find that Death String Quartet music has some mojo...they can actually shred (their bows). Benjamin Britton’s quartets get at it, so to speak.