Warhammer 40k fluff thread VI: They see me Ward'en, they haten

[GolemsVoice]

There IS however such a thing as a black market psyker, which usually means two things: you're a wretch who does the psychical equivalent to prostitution, used for cheap and not very complicated services, or you're a powerful name, recognized as one who has both the power and the cunning to do or even lead complex operations, in which case you can demand quite a sum.

EDIT:

What bugs me is that for every time I hear "The Imperium is too large to cross. To go to Terra is a huge undertaking that not many people have the resources to do" I also hear "Travel time and distance are unrelated. Don't bother looking at the map, it's essentially worthless."

Maybe this essentially means that it is to large to cross with any kind of mundane means, as few people actually have their own ship, and must rely on others for transport. Which means they have to take the detours that their host wishes to make, in case of, say, a trading vessel, those could be quite large ones.
Also, the ships in which most people travel are probably not top-of-the line like the Black Ships. Does the quality of the warp reactor affect the speed in the Warp, and can such a thing even be influenced?