I've had a CARS interior installed on 1967 Impala SS for almost 10 years and it still looks brand new. I think PUI is the only company that makes the door panels, but they are sold through CARS, Inc. I'd give CARS a call directly and see what they have to say about the door panels.
1967 Chevrolet Impala SS convertible - Ermine White C1
1967 Chevrolet Impala SS 396 - Marina Blue FF