While there is no single mod that I know of that can compete in overpoweredness.
My stuff is not indestructable there are a number of mods I find both annoying and scary when I am on the receiving end.
For instance Lafiel's transwarp torpedo render all of my defenses obsolete.
Bloodcult's firepower is close though I pull away around tech 7-10, their giant internal cannons pop any shield below 7 like soap bubbles.
CaptainRedstone's Diffusion Shields 1.1.0's higher level shields are no joke though powering them can be interesting.
In the early game Starwars shields just don't seem to die.
And I will not talk about what happens when a death star super laser hits my armor (its not pretty).
As for Warhammer most of their stuff is pretty well balanced I suspect it would be a good challenge for tier 3 tech since they don't have npc ships (last time I checked) I don't usually run their mod so a really exact scale of their tech relative to mine I can't give out.