I didn' knew of the Orion engines... they look awesome (video review for those like me).
I had a look at TAC and USI-LS, at the end decided for the simpler USI option. I installed it to give bases some reason to be ( and hopefully, with the need of greenhouses, to achieve some kind of self-sufficiency).
As I play on a Mid-2011 MacBook Air, I tend to use as less mods as possible... Althoug maybe performance is not as affected by the number of mods as per the number of parts, never really knew.