BiS for all DPS are the Dread Guard Relic of Boundless Ages and:
Internal Proc Relic if you use tech damage.
Elemental Proc Relic if you use force damage.
Almost. Gunnery commandos/Arsenal mercs should use the kinetic relic, and Combat Sentinels/Carnage Marauders should use the energy relic, because of extra armor pen these specs get. There may be others, these are just the two I'm aware of.