Other than it's effect on surrounding objects almost nothing is known about gravity.Well, the truth is that even at warp speed, the stars on the screen would hardly be moving if any at all, but faster than light travel has been theoretically conceded.
I like quark degenerated matter as well, but no one can say what happens to the quarks once the strong force is overcome.
As to dark matter, I'm convinced it is real, as opposed to dark energy which thus far is just a convenient invention designed to satisfy a gaping flaw between theory and observation, but I also speculate a connection between black holes and dark matter; there is a hidden connection between the weak force of gravity and the ultimate state of the universe. And since gravity causes space to curve back upon itself then time must curve back upon itself as well making beginning and end all relative. In fact, some have speculated that our universe is but a black hole (or a quark) within an even larger universe.
But as of now, I believe we are still completely getting wrong the true nature and role of gravity and its relationship with spacetime, but the important point is to not fall into the trap that the universe is an object, something positioned with boundaries in space and time like a cube you can hold in your hand; the universe is mind, consciousness, and as such, is unlimited, unbounded-- whatever can be imagined can be done because thought creates reality, not the other way around.
IMO figuring out gravity is the key to FYL travel.