Bring back the Douglas A-1 Skyraider!
Maximum speed:
Mustang: 437 mph
Skyraider: 322 mph
Super Tucano: 367 mph
Payload:
Mustang: 2 hard points, 2000lb max
Skyraider: 15 hard points, 8000lb max
Super Tucano: 5 hard points, 3300lob max
Internal guns:
Mustang: 6x M2 .50 cal
Skyraider: 4x 20mm
Super Tucano: 2x .50 cal
I haven't found directly comparable range figures for these aircraft. I think the Skyraider would turn out to have the longest legs as an attack aircraft. The Mustang used drop tanks to extend range, as an air superiority fighter.