If I were the Pistons, I would try to establish Rasheed Wallace down low early and often, especially when we bring in PJ but against KG too. If they go to that early, they may be able to take advantage of KG's intensity and get him in foul trouble. If we sag in to double, they have the shooters to make us pay so we will stay at home on the perimeter and it will be mano y mano. There is really not all that much more they can do. Their game is pretty established. They can't really change things too much in two days.
I think the Celtics showed that they are the ones who can dictate their game. They are going to continue to defend based on their scheme. On offense, the big thing they did better in game 3 was ball movement. Trying to force a high post screen-roll on every posession plays to Detroit's strength. This is all very obvious but they need to move the ball and they need to keep people moving without the ball. The more they did this, the more open shots they got. Scoring was balanced which is a good sign. If Detroit gets behind, they may try a zone defense. Not necessary the extended trapping zone but more of a sagging zone to see how we respond.
Also, even though Pierce had what 11 points, I thought it was one of his best games. He played great individual D (Prince was 2-11 and only 4 rebs) and was like a middle linebacker, making sure everyone else was where they needed to be. He passed when he needed to pass and shot when he had a shot. This was an extreme case of the box score for Pierce not telling the whole story. If Detroit tries to adjust by helping less on Pierce (because of all the points by everyone else), Pierce will adjust and score 30+. They are probably better off staying tight on Pierce and challenging Rondo, Perk, etc to see if they can hit their shots again.