It does slow it down a bit. Originally I put it because it had the Marsh/Swamp terrain included, but the grassland and marsh looked very similar in color so I removed everything except marsh/swamp. Everything for running the mod is in the 1st download (but I\m adding units at the moment, so I might use the Download Database spot for unitgraphics instead of terrain, and then it will be needed.
But... the mod is still in development and is only finished to around gunpowder (Ill try update it around once a week, but lately it has been around improving AI/balancing), and it does not contain neither Revolutions nor BUG UI which alot of people like. It does however add a lot of new stuff and changed values that makes it interesting. Im especially fond happy about the concept changes in movement, as it now becomes a factor to play with (instead of the IMO boring : 1 for men, 2 for horses and 3 for vehicles).