The Home Defense Turret D&D 3.5 E6

[Tvtyrant]

Larry Light, a wizard-merchant who is a retired adventurer built the Homunculus Turret as an experiment in automated weaponry and home defense. Effectively an advanced Homunculus set inside of an iron bell (3 inch thick iron 10 hardness 90 HP) turret is an attempt to transform home defense.

The Homunculus has 9 ranks in UMD (6 from skills, 3 from Skilled ability) and is holding an enlarged wand of Launch Item. Three holes cut in the bell allow the Homunculus to see and fire alchemical items out at targets. The bell is set on ball bearings that allow it to swivel so that the Homunculus can shoot at surrounding creatures. A metal door on the inside of the bell can be slid shut to prevent incoming fire or physical attack, which the Homunculus does if the enemy comes within 60 ft.

Multiple turrets can cover each other for best results, and the turrets have a range of 1160 ft. or 232 squares. Their accuracy within that is perfect due to the Launch Item spells, and they often lob Tanglefoot Bags to hold enemies in place while dousing them in oil and alchemists fire.

The turret is reloaded by the owner handing new alchemical rounds into the lower opening, and the Homunculus' 10 intelligence allows the owner to give detailed instructions on which weapons to use under which circumstances.

The whole turret with wand and Homunculus costs some 15,000 GP. Attempts to make moving turrets are ongoing, with a new invention similar to a four wheeled bicycle with turret on top being the cheapest. This bicycle turret has two Homunculi, one who pedals and one who shoots the rounds. The design is lighter and thinner, making it far more fragile (costs 20,000 GP.)

A much sturdier model is the Iron Tower, which is effectively a cart covered in a metal box which hides most of the wheels in an inch thick iron curtain. Below the cart's axle is four iron defenders who are attached to the base of the cart and are steered by a Homunculus. Two towers come out from above the box to shoot at enemies. The Iron Tower costs 50,000 GP to make and none are currently for sale. The Iron Tower has 110 HP and hardness 10, although it could be made with adamantine to increase the hardness and HP.

[DracoDei]

What makes this particularly E6?

Do Homuculi need to breath? If not, why wouldn't the door usually be shut?