hey there, sorry to hear about your rust problem that definitely stinks when that happens. In regarding your rust problem. If you want to restore your daughters car to its original state I would take care of the rust. I don't know exactly how bad your rust problem is, so I can't say what you can or can't do or how hard it would be to treat it. If you decide to replace the panel that would take less time and hassle with regarding the rust, because if your lower panel is bolted on you can always take out the lower panel yourself and replace it with the new one yourself. Now if it needs to be welded I would take it to some sort of professional, I only say this because I don't know if you can weld it in yourself. If you can I wish you the best luck. If your looking for the lower panel Larry's Thunderbird and Mustang parts, inc would have it. The number is 1-800-854-0393 or 714-871-6432. Now if you don't like there prices you can always call National Parts Depot and the number is 805-654-0468. National Parts Depot part number for the lower rear panel extension is 40544-5A, which is $44.95 and that's without exhaust opening. If you want the ones with exhaust opening the number is 40544-6A, which is $54.95. Now if your tailight panel has rust on it to you can call the numbers I gave you. But to help you further the taillight panel from National Parts Depot would cost you $94.50 and from Larry's Mustang it would cost you $109.95. I hope this helps you with your problem and as always GOOD LUCK!