I wouldn't mind the Mustang Mk Ia and A-36 apache, both served well in the Italian theater, however the Italians need a few planes, Re.2001, Re.2005 and G.55. (Throw in the Wellington X for the British as well or B-17F for americans)
But honestly the Luftwaffe needs the 109g6/AS as much as the allies need the Mk Ia.