yes you can swap planataries the 231s used 3 sun gears and the 241 used 6. I don't know about the inputs the housing may be different. you would be best just calling DD machine and see if he has any 241 kits. He may be able to cut the you the aluminum adapter plate and I think that the intermediate shafts are the same. Always worth a try.
edit: and just to piss you off the kits have doubled in price since they first came out