I'm sure this has been asked here many times.. But i'm new here so please bear with me. I just bought a 2002 Silvarado 2500HD crew cab 4x4 w/6.0L & 4:10 gears

What are the best mods to make to get the most performance. I'm leaning towards the Superchip Max Micro Tuner and a K&N air filter kit. Do you guys recommend a different programer? I know there are Hypertech, Crane, Granatellie, and some other.. And then there is the K&N vs the Airraid air in take system.. What else??? What more do you suggest for the most performance for the money??? Headers? Duel exhaust system?

Thanks for any and all your advice..