Regarding your comment in the video about why you weren't inclined to steal the Very High Thrust Engines tech:
I don't know how things are in the mod that you're playing, but in the unmodded game the unupgraded StarBurner is one of the best sublight drive components in the game. Aside from the upgraded versions of the StarBurner, the only drive thruster components which outperform the unupgraded StarBurner per unit size invested into sublight drive thrusters in the unmodded game are the fully-upgraded Acceleros Engine, the fully-upgraded Vortex Engine, and the fully-upgraded TurboThruster if going by maximum attainable sprint speed, or only the fully-upgraded Vortex Engine and fully-upgraded TurboThruster if going by maximum attainable cruise speed. Since the fully-upgraded Vortex and Acceleros Engines are all the way at the end of the sublight drive thruster branch of the Energy and Construction tree, it may very well be worth your while to steal the Very High Thrust Engines tech from the Sluken even if you never acquire the upgrades.
You can fairly easily get an idea of the relative quality of the various drive thruster components by computing the specific thrust of each component, i.e. the rated thrust of the component divided by the size of the component. Multiplying the specific thrust by the size fraction given over to sublight drive thrusters on the ship gives you the design speed of the vessel (use specific max thrust for sprint speed and specific cruise thrust for cruise speed), so thruster components with higher specific thrust can achieve higher speeds for a given investment of size or require less size to attain a given speed.
Regarding how the bonuses for species within the empire are calculated:
Firstly, if you can get the same type of bonus from multiple species, be aware that only the one which currently offers the best bonus counts. If you have both Humans and Ketarovs in your empire, you'll get the espionage bonus from at most one of them, not both. Secondly, the only bonuses which can show up in the Diplomacy and Government screens are the empire-wide bonuses (Espionage, Colony Income, Research, Mining Rate, and probably a few others that I'm forgetting at the moment). A few of the species bonuses (Colony Happiness and War Weariness, maybe some others) will apply to any colony which has a sufficiently large population of the species which grants the bonus and will never be applied to colonies which do not have a sufficiently large population of that species.
Non-founding species can begin to provide empire-wide bonuses once the species makes up at least 1% of your empire's total population and will give the full bonus listed in the species description once the species makes up at least 20% of the total population of the empire. I believe that the bonus you get while the species makes up between 1% and 20% of the empire's total population is (percentage of the empire's population)/20% * (maximum bonus), though there may be some rounding involved.
I am not completely certain, but the one and only time I checked, it looked like the founding species of your empire will provide its full bonus for as long as the founding species makes up at least 10% of the total population of the empire, and will provide a scaled-back bonus for as long as the species makes up more than 0.5% of the total imperial population. I am also pretty sure that certain bonuses, such as the Ackdarian bonus to maximum military ship size, cannot be lost even if the founding species somehow becomes extinct within the empire.
Also, an anecdote on ship design: I once ran a test which pitted two ships of approximately the same size against one another. One ship, let's call it Ship A, was size-407, had an armament of 8 unupgraded Epsilon Torpedoes and 16 unupgraded Maxos Blasters, was protected by 5 plates of Standard Armor and 5 unupgraded Corvidian Shield Generators, and had a sprint/cruise speed of 16/10. The other ship, let's call it Ship B, was size-406, had an armament of 3 unupgraded Epsilon Torpedoes and 6 unupgraded Maxos Blasters, was protected by 10 plates of Standard Armor and 12 Corvidian Shield Generators, and had a sprint/cruise speed of 34/21 or something like that. Both ships were powered by unupgraded NovaCore Reactors and propelled by unupgraded TurboThrusters. On the default engagement settings, Ship B destroyed Ship A before Ship A could break ship B's shields; when Ship B's engagement stance was set to "all weapons" vs stronger opponents, Ship B failed to penetrate Ship A's shields prior to being destroyed. Just something interesting to think about when contemplating a war against a numerically-superior, and possibly technologically-superior, opponent.
< Message edited by Aeson -- 1/29/2017 5:45:46 AM >