2 questions:

1. Can destroied subsystems be like bc engines be rebuilt? If so has anyone broke down cost/build time of each?

2. Can you target and destroy resource drop points?

Once the health of a subsystem drops to 0 it will be destroyed, so need to rebuild it. If a subsystem is about to be destroyed I usually retire it so at least the RUs spent on it won't go to waste.

Non-subsystems like engines, resource drop off points and such (so everything that is pre-build on a ship and isn't in the consturction build menu for the concerning ship) will be disabled once their health reaches 0, but will auto-repair over time.

Thanks wild,

This opens up some other questions then.

1. Is a damaged prebuilt subsystems less effective? like will an engine that is 50% damaged slow the ship down by a percentage? will a 50% damaged resource drop point increase the time it takes for a collector to drop it's load?

2. how long does it take for a 100% damaged prebuilt subsystem to return to 1% health? What i'm getting at is if a successful strike on a resource sub is accomplished, how long until collectors can drop again? will they sit and wait or divert to the nearest drop point (if this is the case even a 1 second stall could be useful if collectors aren't re ordered to harvest)

simi related questions,

3. Can you target a subsystem with emp? If so what are the effects (stall build, disable gw, stall research)?

4. If you emp a carrier does it disable it's facs as well (stall build, disable gw, stall research)?

As far as I am concerned, subsystems will continue to operate at the same rate until their health reaches zero. So, even a subsystem with 1 percect health would continue to operate at the same rate as one with 100 percent health.

Subsystems auto-repair at a certain rate, but I am unsure what this rate is. If you really want to know you could look it up in the .BIG file using a BIG viewer.
Also, collectors will sit idle near the disabled resource drop-off as they only auto-move to a new drop-off point if the previous one is destroyed. The resource drop-off is a pre-built subsystem on the mothership/flagship and therefore can't be destroyed, so if it's at 0 percent health it's still there and therefore collectors will try to dock with it.

I myself haven't really tried this, but I think it has no single effect. In the Pirates mod however, you could damage and eventually disable/destroy pre-built and normal subsystems alike with the missiles the Pirate Destroyer fires. In regular Hw2, I don't think this is the case.

Capital ships (carriers, motherships) are immune to EMP.

Hope that answers your questions.

"Pre-built" subsystem are called innate subsystems.

1. Definitely true for all engines. BC ion cannon, however, seems to be unaffected until it's completely disabled. Killing ru drop-offs is very rare(you are better off killing collectors), so we'd have to try it out and see. Subsystem repair rate is in the SubSystemTuning.xls file.

2. If RDN data is correct, 40 seconds for ru drop-off points, 90 seconds for hiig BC ion cannon, 80 seconds for engines. Collectors do not divert to another dropp-off point beacuse one of them is disabled, but they do by default try to dock somewhere else if the nearest point is busy.

I seriously doubt EMP can have any effect on subsystems, but you're welcome to try.

The only exception of engine, which will make the ship slow down as engines are getting damaged and will come to a halt once it reaches to 0 health, but again, it will recover over time, dunno how long, in a minute or 2.