It's official, the Giants are switching Tim and MadBum. Seems like the smart thing to do. You have to at least consider the possibility of a 163rd game, and Tim's the guy you want if that happens. Lincecum stays on his regular rotation, and Bumgarner gets more rest. That can't hurt as he's already well past his career high in innings.
If the Giants wind up in a tie with the Padres, and both teams have better records than the Braves, there won't be a tiebreaker--the Padres win the division because of their better head-to-head record (an SF sweep puts them at 8-10). The Giants are then the wild card. If the Braves finish with the best record (among the three) and the Giants and Padres are tied, then the division winner will be decided by the extra game. These are regular-season games, by the way, not post-season games. If the Giants and Braves tie for the wild card, they play a tiebreaker in Atlanta (due to SF's 3-4 record). A three-way tie would first require a division tiebreaker between the Giants and the Padres. The loser would then play the Braves for the wild card. (links here and here)
So I think it is best to up and win the division outright, don't you?
For a little relief from the torture, check out Frank Zappa and his band doing "The Torture Never Stops."