TTI's new X-pipe (on the left) was easy to swap out with tti's 7-year-old H-pipe. We were pleasantly surprised. We used hi-temp anti-seize. Most combinations will see definite improvements in the mid-range torque and horsepower using an X-pipe. on the R/T, the X-pipe delivered a smoother idle and powerband with an improved 60 ft. and e.t. The X-pipe also impressed us with less sound decibels to deal with.