I can highly recommend Chris at WASP in Elm, Wisbech for all american car parts. Panels, tuning bits etc etc.
They have an ebay shop, but cheaper if you call and order.
No connection other than I am a happy customer, and he is just up the road from me.
WASP 01945 588091
His prices put people like usautomotive.co.uk to shame
Oh quick deliveries too, normally the next week as they ship every week unlike a lot of suppliers!