How an Italian change of sides would alter the Mediterranean war

A German attempt to restore Mussolini would open another front across mountainous approaches to Italy. Routes through Austria, Switzerland or southeastern France would present difficult terrain for maneuver. Italy could invite RAF heavy bombers to bases in the north, provided those forces could be supplied. Without Italian support, German operations in the Mediterranean would be much more limited, even with U-boats still available. Italy had a larger battle fleet and more heavy cruisers than Germany, as well as destroyers and submarines within a balanced fleet. Removing that force from the Axis would change the naval threat faced by the Allies. If Italy then joined them, the same ships could become an additional Allied force.