I live in Elon College, North Carolina. I have a 2005 Tahoe 5.3l 4x4. I have a flow master 3 chamber cat back exhaust and a full k&n intake. I am wanting some more power for pulling and more gas mileage if possible together. There is a place that does custom Chevrolet tuning around here where I live(RPM). They are supposed to be great when it comes to GM motors. I'm thinking about getting it tuned by them and maybe some headers. Will the headers help or hurt my gas mileage and what kind of power can i expect? What are some good headers to?
Should i change my exhaust to true duals and get rid of the cats and go with high flow cats or no cats at all or just leave the exhaust like it is???
thanks for the help and sorry for it being so long.

Dustin Morris