Help On Dunlavy's

Looking for information on upgrading parts in crossover in Dunlavy SC 4A's. A friend and myself both own Dunlavy speakers and we like them very much. We also believe that they can be made better with better crossover parts. Upon inspecting the crossover we found a lot of the values were removed. We contacted Dunlavy and they refused to give out the information. So can anybody tell us who might be able to help us. Our only objective is to make a good speaker better.
Thank's, Chuck.