We knew this unit would be good coming into the season, but they’ve exceeded expectations through two weeks Through three games, the 49ers’ defense allows just 9.3 points per game. They are allowing just 227 yards per game, nd boast the number one pass defense and the fourth-ranked rushing defense. They have allowed only nine points over their last two games and have yet to let an opponent break 20. Their ferocious pass rush has generated a 44% pressure rate thus far, the secondary has been solid, and they have allowed just 2.8 yards per rush. They have been the…