Hi, you won't "lose" anything whether X or H. I believe X will give increase in HP, H increase in Torque. It would be such a small increase in either pipe. The sound it makes will be more noticeable then any gains. Personally I never heard a V6 with either one but would think an X would sound better with a chambered muffler. That's a biased opinion though, cause that's what I have in my GT. I tried magnapacks (straight through) and after @ 5k miles it was too loud so I swapped out to flows. Good luck!