I think Dallas beats the Heat no matter how much rest they get.
The Heat are going to be vastly overrated heading into the Finals (assuming they make it, of course). They struggled with the Bulls, they beat an equally overrated Nets team, and they will have beaten the Pistons, who are clearly not the team they were in the past two years. Meanwhile, Dallas, should they make it, will have pulled off the only sweep of the playoffs, beat the defending champs, and beat a very tricky Suns team.