R.E.A.R.M. - "Rearmament Expansion And Redesign Mod" is an unofficial Homeworld 2 expansion and it adds number of new interesting and various units.
I highly enjoy playing this mod - the new ships are extensive, though it is buggy in game, that is due to homeworld itself, not the mod.
I love the renaming ships feature, as it is great for RP multiplayer, and though it would be a shame not to bring that into REARM V2, i can understand why. the modular ships are brilliantly modeled too, all the parts fit perfectly, and the ships which are added into the game look great.