@Midnight Kitsune: What about playing Exerelin with less planets/systems/factions? 
Mainly because I have a craptop. An example: with nothing but SS active, I have the following FPS and idle percentages with only your mod, Kadur Theocracy, Omnifactory, Lazylib, and bounty hunters active:
Menu: 56 FPS, idle 30%
Campaign overworld, no fleets visable but my own and paused: FPS: 63, Idle: 28%
Campaign overworld, no fleets visable but my own: FPS 52, Idle: 6%
Campaign overworld with ONE tritach SDF level fleet and paused: FPS: 50, idle: 17%
Campaign overworld with ONE tritach SDF level fleet: FPS: 43, Idle: 3%
Battle screen in a fight with tritach SDF level fleet, no ships visible: FPS 52, Idle 3
Battle screen in a fight with tritach SDF level fleet, no ships visible and paused: FPS 54, Idle 3
Battle screen in a fight with tritach SDF level fleet, no ships visible, on the "fleet control" screen: FPS 45, Idle 30
One salvo of missles fired at a single, radar visible enemy: FPS 45, Idle 3
Two live enemy frigs and one dead one: FPS 30, Idle 3 (paused: FPS 45, Idle 3)
Basically what I am saying is that I have a very bad craptop.