Morning all - I've searched around and just read Jenna's sticky on the difference in closed and open. Great info. Some of the threads concentrate on HP though. Not really interested in that on the 'burb...need ways to improve MPG. My wife and I now now drive to work together. We take her suburban now cause my '86 needs a few window and door gaskets replaced to quiet it down It's 70 miles (interstate) round trip everyday. Fuel economy is still good, I think, but I know there's things I can do to bump it up even more. The 'burb is a 2004 1/2 ton. Everything is stock. From reading everything, I know I'll need to upgrade the exhaust, but for right now, I'm just looking at the CAI. Will it be worth it to just do that or should I wait till I'm ready to tackle the exhaust as well? Also, will it really be necessary to reprogram anything? Thanks for the info ya'll!!!