Burn 20 for all requires Navigation 3, which is a huge opportunity cost. I would love to fit Navigation 3 on my characters, but never have the points to spare. Thus, I get stuck at burn 16 or something similar, which is not too bad when the AI moves at sub-10 speeds. This is a reason why I scuttle capital (D)s with Degraded Engines, because it will drag my fleet's (sustained) burn down.
As for stealth, I would need to keep my fleet small, and even then, if I try to go somewhere like one of major planets in Askonia or Hybrasil, there are enough enemy fleets that either one pings a sensor burst, or one just blunders unaware toward my fleet, but my fleet is too slow to get out of the way (due to being dark). If I want to smuggle (buy or sell) thousands of cargo, with lots of warships and Atlases in my fleet, I simply make the mad dash to a planet, and if the guards were distracted by something else (like chasing pirates), the planet is clear and I get to shop at their black market (maybe buy lots of organs).