What do you fine chaps think was a more impressive feat?
Michael Spinks move from Light-Heavyweight to Heavyweight, after a 4 year reign as champ at Light-Heavy with 10 successful title defenses without a loss, and the unification of all the titles, to then go on and beat an undefeated Larry Holmes (who is quite possibly a top 5 ATG heavyweight) not only once, but twice, and fighting and defeating him at a weight that was 46 pounds outside of his original weight class.
or
Pacquiao moving from From Flyweight (112) to 150 and winning 8 titles with 6 total successful defenses (2draws) and beating an unranked Margarito for a vacant Junior-Middleweight title at a catchweight of 150, 38 pounds outside of his original weight class.
Michael Spinks move from Light-Heavyweight to Heavyweight, after a 4 year reign as champ at Light-Heavy with 10 successful title defenses without a loss, and the unification of all the titles, to then go on and beat an undefeated Larry Holmes (who is quite possibly a top 5 ATG heavyweight) not only once, but twice, and fighting and defeating him at a weight that was 46 pounds outside of his original weight class.
or
Pacquiao moving from From Flyweight (112) to 150 and winning 8 titles with 6 total successful defenses (2draws) and beating an unranked Margarito for a vacant Junior-Middleweight title at a catchweight of 150, 38 pounds outside of his original weight class.