Brother, not friend, but the point was, he gets identical numbers that I do when I play my rogue. I had to go take care of a minor emergency and asked that he hop on my toon for the pull, simply put.
He uses rupture, I use rupture, there was no difference there. The biggest difference is that he's a little sloppier with CDs (he pops killing spree after trinket, but before blade flurry, which to me is a no-no).
You can say what you will about stat priorities. I was gemmed full AP when I first hit 80. Then, I looked at my brother's toon, which is gemmed primarily ArP, and decided to give it a try. With all the gems I could afford to replace ArP, every time I replaced one, the DPS went up (on 10 minute dummy test runs). Then, when the AH had no more ArP gems, I used a few Agil gems I had bought as a just in case, and replaced the rest of my AP gems, and again the DPS went up (in both specs).
I'm curious. Are you telling me my stat priority is wrong for Sub or for Combat? Quite frankly, saying it's 'wrong' for sub is total ********* since no one REALLY knows how to play Sub. I've seen a theorycrafting thread on EJ, but it was all over the place, and they kept using sims as their reference.
Lemme tell you something about sims. They use a theorised stat weight system based on whatever you (or the sim dev) put in, and a rotation they put in. The sims are based on theoretical knowledge, and in the case of a spec like Sub (or Frost Mage) it's often times just WRONG.
My version of RAWR isn't absolutely up to date, but plugging my rogue into it, I get more DPS from my sub spec than they do. It was the EXACT same way with my Frost Mage.
My next statement is almost (almost) nullified by my previous, but when I put CQC spec in and equipped my rogue's dagger + a 245 dagger in her off hand, the SIM came out to the same numbers I realistically achieve as Sub in the game (6200, perfect conditions, no Hellscream buff. I did 6k on BQL last night with no bite, only having one triangle connection dealy. HnS was above, 7K average, as low as 6400).