It's possible that Justin Smith is the best defensive lineman in the history of the NFL. Or Superman. Or, at the least, Batman.Sometimes, that's the way it seems as the 49ers head into a matchup against the Seahawks in Seattle Sunday night.With Smith out of the lineup last December with a triceps injury suffered the week before, the 49ers were mauled by the Seahawks 42-13.After having beaten Seattle in three straight meetings – all with Smith starting at right end in their 3-4 alignment – the 49ers fell quickly behind, 21-0 in their December clash and gave up 346 total yards to Seattle.Now, with the teams getting ready for their first meeting since that game, NFL observers and the 49ers themselves say Smith's return will make this game much different."With Justin Smith out with a torn triceps, (linebacker) Aldon Smith pretty much became a non-factor," wrote NFL analyst Elliot Harrison, in his preview for Sunday night's game. "Things can't go that way in Seattle this time."Watch Justin Smith over the course of any game, and you see a defender who must be accounted for on every play. He is relentless, against both the run and pass, and his strength and technique allow...