The Diamond Eye intermediate pipe is listed as a 3.5-inch driver-side first section intended for the vehicle's intermediate exhaust run. The description references an AL construction option and a weld-on flange-to-adaptor, and specifies application to 2008 Titan gas configurations in the product text.
Diamond Eye INT PIPE 3 5in DRV SD 1ST SECT SGL/DL AL 08 TITAN-GAS APP WELD-ON FLANGE-TO-ADAPTOR