Originally I wanted to form and weld a 3003 inlet for the tunnel, however, after making the first run of the parts it was apparent that that process was going to require a fairly sophisticated jig in order to weld while maintaining the proper alignment. That was going to take more time than I wanted to spend, so I ended up making a fiberglass mold on the parts I had fabricated. I also placed a doubler on the aft end of the tunnel, as it was fairly flimsy after cutting it back so as to allow clearance for the cowl flap.