After tape watching research, I am leaning with Poirier, at least for the first 2-3 rounds.
Pettis may have a better technical striking, switching stances, and combining with kicks and body shots, but Poirier is a bit more unpredictable due to the fact that he is a southpaw. Pettis is also a bit better with jiujitsu, but I don't see him submitting Poirier.
However, Both have two glaring weaknesses; Poirier has a weak chin, and Pettis has a damaged RIGHT EYE. Yeah, it is damaged, you can notice from the moment he is hit near that eye, it inmediately starts to sweall up and he starts blinking. I might be exaggerating, but this is what I saw.
I believe that if Poirier hits Pettis with a left hook, that eye would be messed up and Pettis won't be able to keep the same pace for the next rounds. And Pettis has hurt his eye in four out of his last five fights. So, my prediction is that if this fight goes late, he won't be able to win a decision.
So, It is Pettis by knock out or he losses (by decision or finish).
Prior to researching the fights, I was leaning Pettis by decision, due to the fact that he is more technical and has better cardio. But Poirier cardio isn't bad, he will hold his own in a 5 rounder. So you can see how all this changes with a little tape watching.