Truck Forums - New join with a 2008 Silverado 4x4 LT

Hello Everyone,
Just came across the site and wanted to be a part of the team. I have 2008 extended cab 1500 with 4x4. I would like to get some of your opinions and suggestions. I currently drive about 90% of my travel on the highway going back between Harrisburgh, PA to Pittsburgh, PA- 210 miles each way, twice a week. I am looking at things to increase my gas milage, free up power and get more bang for the buck. This is what I was looking into;
1. add cold air intake- looking at AIR RAID... anyone using it or have a better system?
2. add power chip to retrain the computer for the air intake, looking at Edge programmer. Seems to be good bang for the buck and has a nice modual that fits the dash.
3. open the exhaust with a Magna Flow 2.5 Cat-Back system. Not sure wheather to go split dual or just single behind the tire?

I done some homework with this, but you guys have tried these things, so I value your experiences. Am concerned with the warrenty and emissions. What is the real deal?
Thanks I look forward to the help.
Joe