All I really did was remove the molding that is supposed to match up to the original airbox. No big shakes really, after seeing what some guys on this site can do with fiberglass. The after market covers I had were pretty busted up, so I reinforced the tabs all around, patched a hole, and trimmed them down as small as I could get them. The only remotely tricky part was carrying the contour of the edge around to fill in where the previous molding was not... The last picture says it best I think.