Questions first

I have been playing around with damage a bit, using some old ideas I have made work in other games to simulate damage.
I need to use alpha textures, and wondered how this was implemented best in the SCP builds. What format works best etc. Do alpha textures put a greater drain on framerates?
Also, when it comes to sub-objects, what sort of limits am I tied to? Also, when a subobject is destroyed, can I replace the model with a damaged version. I think you can do this with sub-systems...is that the same thing?
Finally....if a subobject has a turret on it ( can you do that??? ) what happens to the turret when the subobject is destroyed?
Basically, the plan is this :
Build the base model as a 'frame'. Just a central spine with ribs and some basic boxes to simulate bays and such like. Not too complex, since this is not going to get seen very much. Then, make the outer hull up in sections, each as a sub-model. When a hull section is hit and destroyed, you will see a hole left! IF I can swap in a damaged version, I can make a nice burned through effect. Naturally... this is only relevant for capships...small fighters can just go boom into lots of little pieces

Oh...and the request

Is it possible, in some future build, to make afterburner fuel a resource that gets used up ? Leave the ordinary engines as they are, but when you burners fire, they should have a limited life until you re-supply. I know this has AI implications ( since they wouldn't use the fuel sensibly....but it could well add to the immersion factor!