What someone else said already, what's your specific situation/spec. As a corruption sorc, I just used Xalek and altered between healing/bubbling him and putting dots to help dps and interrupt whenever possible. I moved out of his aoe (force storm) when I couldn't interrupt and didn't even bother to move Xalek and just healed him through it.

I like the Voss social gear set, but as others have said, it requires social 5; and, unfortunately only at social 2 at the moment. My female assassin (darkness spec'd) was wearing the slave girl outfit but noticed it was bugged. Adding/replacing mods will give you the correct stats but loading into another zone would somehow diminish the stats. Switched to the imperial dancer outfit and transferred the mods (back when she was in her low 30's) and noticed a 2k HP gain. Don't know if that bug is fixed yet. PS - kinda fun to tank in the slave girl outfit and joke around that I hold agro by flashing the mobs LOL.

That is a mystery more difficult to understand than the force itself I haven't seen a purple crystal/lightsabre yet on my server.

It seems like you don't get the higher grade version as often as the other items you can craft; however, I was successful in getting one from RE'ing. Guessing the chance rate is much lower.