Combonly combines turrets into their combo shooting version. So if you have a nuke combo going, drop a combonly next to the combo, then wait for it to go red (it will flash red/blue, click when red and it will wrap up all three turrets into one turret that fires only combos. It will not fire the combo any faster, but it will save real estate. Combined with being able to move the turret, you should be able to make some crazy long runs now