Who cares if Colemans on steroids? Its not hurting any of us if he takes em or not. The old-school Coleman was an ANIMAL and would destroy Shamrock.
Best case scenario: this fantasy matchup takes place in UFC 2 when they were really fighting. Without a bunch of pansy-ass rules to protect shamrock when he pulls guard, Coleman would make a bloody mess of him within 5 minutes using GNP and the single best weapon against the guard, the headbutt.