Looks very much like that chassis has been designed for one of the SCX shaft-driven 4x4 motors. There's a cut-out onder the front axle for the crown wheel to power the front wheels.
So add about 15 quid for the motor (Pendle seem to have a couple of types in stock) and a second crown gear and you'll have the Integrale as it should be....
So add about 15 quid for the motor (Pendle seem to have a couple of types in stock) and a second crown gear and you'll have the Integrale as it should be....