I have a 2002 tahoe z71. I upgraded my spark plugs at the 100k mark to ac delco iridiums and I noticed an instant response. Now I'm working on a diablo trinity system, and i was curious if there is other stuff that I can do that will help me increase my MPG since my job requires lots of driving. Will CAI, headers, and dual exhaust help me achieve this goal? and if so what product does one use for the best response?