I have a W107 380SL....super smooth motor mated to a 4 speed auto, but you have to make sure engine oil changes have been regularly carried out by the previous owner. The 560SL is no different in its make up other than being more powerful and torquey obviously plus other improvements over the 380SL. The most common things that will require doing on high kilometer cars are the head gasket, timing chain and all timing chain upper and lower plastic guides, valves and valve guides. It is a big job which can be done by a knowledgeable individual DIYer as the dealership will charge you around $15k+ for a proper rebuild with all genuine/OEM components fitted. Around $5k + will buy you an upper engine rebuild which in my opinion is pointless. The engine has to come off the car in order to remove the oil pan and then only you can access the oil pump, lower timing chain plastic guides etc. If you go to the extent of taking out the engine you might as well check if the piston rings and crankshaft bearings are within specification. The earlier engines were a lot more robust and less refined. I have experience with the early D-jet (electronic fuel injection) W107s and the later K-Jet (mechanical fuel injection) W107s which were mated to an almost unbreakable 3 speed auto. You have to request that the car is started cold in your presence to listen to any unusual noises mainly known as the famous "rattle" which means your guides and chain will require replacement. Just my opinion on buying a cheap W107.
Yem