Ive got a mate converting a MK2 XR2 to RS Turbo, he went to the local scrapper, cut open a tank, removed the swirl pot assembley, then cut his tank open, put the swirl pot in and welded it back up. I don't know how well its going to work as the car isnt finished yet, but the theory is there. I doubt the fiesta centre would sell the tank if it wasnt any good, should do the job