It seems to me that of all the people on Wisteria Lane, the one you most don't want to mess with is Lynette Scavo, she will eat you (and your children) alive. Why then, I must ask, did Dave think it a good idea to tell the police the Porter started the fire? Dave may be out for revenge and all, but not against the Scavos. I get that Porter was an easy mark which was why Dave implicated Porter and threw the suspicion as far from himself as he could, but surely he knows that such a move is only a temporary solution, yes?
I guess that it's possible that Dave figures that he'll be able to deliver whatever sort of vengeance he has planned for Mike prior to his getting caught lying about Porter, but it still seems like an ill-conceived plan. The police, at the time he implicated Porter, didn't even have Dave on their radar, except as a hero. Handing up Porter as a suspect can only serve to shine the light more on himself.
Plus, like I said above, Lynette is the person you want to antagonize the least on Wisteria Lane. Attacking that woman's family is just asking to wake up one morning to find your favorite horse's bloody head in your bed. If she figures out Dave finger Porter for a crime he committed she is going to destroy him. I can't believe Dave doesn't know that, which again leads me back to his figuring that whatever he's going to do to Mike he plans on doing quickly (and that Dave doesn't care what happens to him once is revenge has been exacted).
Only two other things really caught my eye yesterday (no pun intended). First off, Carlos gaining his sight back. I think it was a good move for the show to not drag out the blindness plot. There was no way they were going to leave him blind forever, so having his sight come back sooner rather than later seems like a good move.