99-06 GM P/U Reg Cab SB Force II Exhaust System RHO The airbox and lid are

The airbox and lid are molded from a composite material that has been chosen specifically for its ability to resist power robbing under-hood heat and the design provides for a completely sealed air box

and calibration

Exhaust System - American Thunder - Axle-Back - 3 in Tailpipe - 4 in Tips - Stainless - Black / Natural - Coyote - Ford Mustang 2018-21 - Kit

'Dinan's high flow intake system for the 550i dramatically increases intake air-flow volume and velocity as well as ensuring the lowest possible intake air temperatures for maximum power gains

and no downside by upgrading to the Dinan High-Performance Intercoolers for the N63 twin-turbo V8

99-06 GM P/U Reg Cab SB Force II Exhaust System RHO The airbox and lid areExhaust System Force II Cat Back 3 in Diameter Single Side Exit 3. 5 in Polished Tip Steel Aluminized GM Fullsize Truck 1999 2007 Kit