Ok I waited awhile so I could give a good review. I put the exhaust on to help with power and gas millage and it has done exactly that. The 2012 Chevy Colorado 2Lt. 3.7L 5cyl. got horrible reviews for the 2012 consumer report for gas alone and this exhaust actually helped. Before I counted getting between 14 and 15mpg moderate heavy foot and now getting 16-18. Plus I like it cause its not awfully loud to were it pisses off neighbors but has a nice deep rumble to it. Highly recommend this!!