from Lowes. I found it in the outdoow plumbing tubing section. I just ziptied the tubing end from the duct, once I got it over the duct. The tubing was around 2.5" in diameter and fit with little trouble. I plan on plastic welding the duct tubing to the inner fenders. I figured that was the best way to make it look professional. But I imagine other fabbing techniques could be used with less of a clean look.
BTW- Am gonna pick up a plastic welder kit at eastwoodcompany.com for not too bad of price. But still keeping my options open. I'll let you know if I find a cheaper price on the these kits.