All 4 IG-88's vs. Boba Fett on foot, Coruscant Streets
All 4 IG-88's in their IG-2000's vs. Boba Fett in Slave 1, space above Coruscant

I think the Fettster would win both, he beat IG-88 B in Bespin City, and IG-88 C and D above Tatooine