Have you played into later into the game yet? Does having additional models affect game speed. It's slow enough as it is on my computer.
it should not affect the AI's thinking time, but I do not known if it affects scrolling time on the map. It does not on my computer anyway (but it's really not representative)
the mod could be load with an existing savegame, you can try to activate it on a later game and compare. I'm interested by feedback if this seems to be an issue.