i am planning to transplant the motor from a 1982 240d into a 1979 240d. while i have the engine pulled i would like to address anything that can only be done with the engine out. the transplant motor does leak some oil and i would like to address this issue for sure. what are all of the items that can be replaced to ensure it will be leak free once installed? also, any tips, tricks, or experiences that could help are MORE than welcome!