go with an AEM V2 CAI...for that car they make extremely good gains...check out AEM's website for the dyno charts. short ram intakes work better on some cars than others, but not on the 03 AV6. that engine responds extremely well to the V2 as well as other mods. http://www.aempower.com/product_intake_app.asp oh, and dont be scared of the prices listed on the site haha you can find the V2 for hundreds less than what AEM lists it for