I don't know of many engines that have had to be rebuilt. They are a very strong engine and with the proper maintenance (which yours gets) it should go many more miles before you need to do that. I would say that the valve covers could be done by you but the others may need to be done by the shop. Some of the members down in OR have done the valve covers and have said that it is a fairly easy job. You could talk to them at the maintenance meet.