I noticed a different with the gibsons. Better MPG. throttle response, more power througout whole power band, I also did a complete exhaust, headers, to x to mufflers. Might not have got a whole lot of power, but my dakota definatly is distinct by it's sound. I get asked all the time what do I have under the hood, and I have to tell them that heads and cam are still a few months out and they just look at me like damn. I say buy the gibsons and do a FULL exhaust. Please have 70mm tb, intake, and full exhaust,or the headers won't do a whole lot for you.