I am thinking about getting a programer/tuner for my jeep but i have heard quite a bit of bad talk about them. Messing with your vehicle's computer Pre-programed codes. Has any one ever played with one of these before? I was thinking about getting the TrailDash tuner from Superchips. http://www.4wd.com/Jeep-Engine-Perfo...t_pn=SCI438753