Well, its not so much adding components, as taking away components and facilities
They should not be able to colonize, or make much use of colonies.
The things that are useful to add are:
- cheap, low tech boarding parties. (probably much less powerful than normal, but available in large numbers because they are so cheap)
- Large resource storage facilities. (They will have few planets under their control, so they have to save for a rainy day)
- more fighter options, and small ships.
What I've been adding to P&N for v2.6, is the ability to cloak undetectably. Basically, the pirates can pretend to be regular citizens, and be noticed but ignored until they are ready to attack.