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've got to say the design of the new layout isn't mine, it's based on a kitbash concept version made by Alex "Howitzer" Alvarez (HowitzerNAM on moddb), but it's a pretty close copy of it because I bloody loved it. It's also very rare to see a "moar guns modification" that's actually really good.
I have long range turrets up there (longer range, less damage than Ion ones) and flaks on the smaller platforms. It's worth noting the M.I. Complex already has their own guns prepared and they'll have a six-barrelled turrets in the main slots.