@Daedalus007
I don't know how the client uses the mods. If fully loading at startup, loading would take longer at Ultra compression. (Might be noticeable at slower pc's). If data is picked-up along the way the client might uses more of the pc resources. (What client crashes, hangtime, ect.).
And why compress to Ultra, mods are not that big (if compared to the B/W rom)....
Please correct me if I'm wrong.