Not to scare anyone just my experience. Wouldn't trade my 6.4 for anything. http://youtu.be/dGj2bIighQ4 This is where I'm at now. Deleted at 42K currently at 71K. I have been running, Snow Performance MPG Max since 41K until 69.5K with H&S, S&B and 5" DP back, when 71mm, Z-max, 6.0 manifolds...