If you cut the airbox, I recommend cutting out only part of the front panel. That's the best place to get more air, and cool air. You don't want warm air from the engine compartment. Since the airbox is right behind the grill, you'll get cool air coming in the grille and into the opening you cut out of the front panel of the airbox. IMO you only need to cut out the bottom 2-3 in. of the front panel to provide more than enough of the amount of air that the engine can can suck in and use and needs.
Bright Red 2003 Edge Plus, 3.0 liter, reg. cab, 4WD, manual trans., 4.10 rear end.
Mods: Speedliner spray-on bed liner. Air box mod. K&N drop in air filter. Gibson Sweptside single pipe catback system. James Duff traction bars (above the springs type). Delta Industries black polyethelene truck box (mounted on the driver's side of the pickup box between wheel well and cab). Hidden Hitch receiver hitch. Side window visors. Door pockets.