Tarver would beat the brakes off of Barkley. Barkley's aggression would not serve him well against one of the better counter punchers that the light-heavyweight division has seen. Plus, Barkley was not a natural 175 pounder. Tarver was.
Tarver by a large decision or stoppage. Magic Man's southpaw stance, jab, and accuracy would have been decisive against Barkley, a warrior who owes much of his fame to his two victories over Hearns. Aside from the Detroit Cobra Barkley has lost to all the top fighters he has faced, Toney, Nunn, Duran, Benn, Kalambay and Maske.
Strong likelyhood this looks like the Maske bout for Iran. 175 is not his best weight and that level of competition does him no favors.