I currently have an 06 LLY STOCK exept for the 4inch exhaust and guages. I am averaging 18MPGs mixed driving 80%hwy 20%city every day. Which right now is the bulk of my driving. I DO average 22 on the hwy only. I have been presented with an opportunity to swap some equipment I am not using for a new 5inch stainless Magnaflow turbo back.

My question is, does anyone think there are gains to be be made going from the 4inch to the 5inch? It looks GOOOOOOD!!!, but that doesn't necessarily translate into gains. I am rationalizing that it may increase my mileage a little more, I will probably have to change my intake to see any more MPG gains.

Just asking for some more info or thoughts. Always looking for those 'extra' MPGs