From the pick six that closed Candlestick to a pair of goal-line stands in Carolina, it seems like whenever San Francisco needs a big play from its defense one of the 49ers' decorated linebackers steps up.With Pro Bowlers NaVorro Bowman, Patrick Willis and Ahmad Brooks playing alongside talented pass rusher Aldon Smith on coordinator Vic Fangio's defense, the Niners' version of the fearsome foursome has played a major part in their advancement to the NFC title game on Sunday night in Seattle.Bowman, Willis, Brooks and Smith have combined for seven sacks, one forced fumble and an interception in road playoff wins in Green Bay and Carolina that set up the showdown with the Seahawks with a spot in the Super Bowl on the line."We just try to stay together and lead this defense," Bowman said. "We all can do special things that a lot of guys can't do in this league. Vic's just done a great job drawing up the right plays and what he wants us to do out there. We're blessed to have all four of us on the same page."What makes this unit so effective is how well they work together. Smith and Brooks are elite pass rushers, able to chase down quarterbacks with their speed and...