Re: 98 Bulls vs 11 Heat
98 Bulls. Even though they were the weakest championship Bulls team, they were a complete team that didn't have an almost non-existant offensive playbook. They also had great defenders at every position Miami is strong at (SG, SF, PF), AND had better pieces around them. I would go as far as to say current LeBron/Wade/Bosh, was better than 1998 Jordan/Pippen/Rodman (combined that is, not getting in to who's better at what position here), but they were a championship team with a great coach, great team chemistry, and the experience to pick teams apart for W's without going into too many dry spells offensively like the current Bulls.
Heat could potentially take a series, but I'm going to go with the '98 Bulls since they were a proven team that was winning it's 3rd title in a row, while the current Heat is only just coming out of it's infancy stage.
Now, if we're talking 96 or 97 Bulls. . .Bulls win the series almost every time. 1% chance of Heat win.