2005 Grand Prix 3800 Non Supercharged. I am looking for a cold air intake. I know many people reccomend using the box style set up and building one but what about a cold air intake such as this: Air Intake Pontiac Grand Prix GT GTP V6 2004 2005 2006:eBay Motors (item 350217425925 end time Jul-23-09 21:48:31 PDT) do that actually work? Are they worth it? Thanks!