I started with installing the long tube headers and cat back exhaust, which was WOW a great improvement on my jk 3.8’s performance. Now I have flashed my pcm with the 87 octane map. I did see some performance increase, but what I am most impressed with is shifting patterns of the transmission, and throttle response. I don’t care what anyone else says, the Ripp long tube header, cat back exhaust, and Diablo retune brought new life to my 162,000 mile jeep jk 3.8 drivetrain.