Something I also would suggest is to add features so they attack on random basis. Also so they just fly around and disturbing your trades, destroying your crystal- and metalextractors.
That would be really cool. They could both send out raiding partys and small fleets to raid your trade lines (not for the bounty, on thier own, like real pirates). Another cool idea would to give the pirate base wepons, not just the turrets, but like a star base (if I was a pirate, i sure as hell would put some big guns on my base), then after you capture it, you would have access to the wepons as well. Very useful since most pirate bases are located at a choke point.
