Tom,
Obviously, the better the condition of the engine will determine if it is a candidate for turbo/supercharging. A leakdown test is highly recommended to test the cylinders for holding the boost. (ex. if your rings are bad). There is no particular year in the 124 M103 that is better for turbocharging. Although, the newer the engine the better. The M103 stock is a hot running engine off the bat. You should do the best you can to eliminate as much heat as possible from the engine compartment and the intake. I plan on ceramic coating the exaust parts and adding an intercooler to the system.
Good Luck!
Adam