This article implies that bolting on longtube heasders with aftermarket cats and doing nothing else, there's 35 hp to be gained. Appartently, no tune is needed and they are using the stock air box. The factory headers look like they should flow well. I wonder if the issue is really the cats? Unfortunately, the side exhaust is lost. A 35 hp gain is impressive, isn't it? I also found it interesting that the install of the Steeda CAI gave them only an extra 10 hp. Here's the link:
http://www.stangtv.com/tech-stories/engine/let-it-breathe-2012-boss-302-intake-and-exhaust-install/?utm_source=rss&utm_medium=rss&utm_campaign=let-it-breathe-2012-boss-302-intake-and-exhaust-install
http://www.stangtv.com/tech-stories/engine/let-it-breathe-2012-boss-302-intake-and-exhaust-install/?utm_source=rss&utm_medium=rss&utm_campaign=let-it-breathe-2012-boss-302-intake-and-exhaust-install