I'm with Wereboar. I did my templar quest after the Rapax away camp, which is where you start the T'rang/Umpani Alliance quest. People that tell you that you have to pick either Umpani or T'rang aren't fully in the know; you can ally with both of them, but you can't blow up either the Umpani ship or the T'rang ship. This alternate route will net you 600,000 MORE quest bonus experience than if you choose the Umpani or T'rang routes.

-Dedzy

I usually become a templar but then make the rapax hostile again, either by doing the alliance or just starting killing them again.

Dedzy: You can still do the final quests for umpani and t'rang after doing the alliance (and get 100k experience for each)