Firing Port and/or Smart Turret, for Doberman in Bulldog Options

[Riley37]

RAW: A weapons mount per SR4 RAW costs ¥2500, is limited to LMG or smaller, and any vehicle can have up to BOD/3 mounts.

What about installing firing ports, so that a gun-drone (eg Doberman) inside a large vehicle (eg Bulldog stepvan) could fire its weapon at targets outside the van? I visualize this a bit like a pirate ship's cannons, inside the ship and firing out... but higher tech.
They'd have limited fields of fire. Placing the gun-drones at weapon ports would probably take up extra interior volume capacity (compared to piling them into as small a volume as possible). A Called Shot might become possible, eg targeting the gun-drone and bypassing the van's armor, maybe even firing a grenade into the stepvan via the firing port.
What about a "roof rack" that allows a gun-drone to sit on top of the stepvan, with the fire arc of a turret (360 rotation but limited depression), outside the stepvan's armor? What configuration would allow minimum time to mount and dismount? (presumably this would attract unwanted attention in civilian areas, eg if any standard GridGuide security camera sees a stepvan mounting a gun-drone, local cops/security would respond with immediate APB and HTRT dispatch.)

Would those also be usable as firing ports by metahumans inside the van?
What's a reasonable cost, and other consequences, of installing a metahuman-only firing port?

If you have worked with military vehicles, especially APCs with firing ports, or have done alteration work on van-size vehicles, or otherwise have relevant direct personal experience, please say so.

Alternately, what about a "smart turret", a weapons mount with a built-in Pilot that only runs the gun in that mount? A Bulldog has BOD 16, and thus could have up to five weapons mounts, one run by the vehicle's base Pilot, and the other four firing independently; that's lotsa firepower (especially since Pilots get 3 IPs). Of course, a Bulldog that's been altered into a gun platform probably doesn't have much cargo/passenger volume left.
A Pilot that's specialized to only run the Target autosoft ought to be cheaper than hardware and software that can do the same, plus drive a vehicle, plus run Electronic Warfare and all the other standard Pilot abilities. Any suggestions on reasonable cost?