Nevada, to say "that nothing is different between now and the regular season when it comes to the Patriots and Chargers" is just flat out wrong. Again, the two teams played back in September. Chris Chambers wasn't even on the San Diego roster at that time, and Vincent Jackson wasn't utilized in the manner that he is now. Those 2 men will be the Chargers prime receiving targets today.
In addition, the Chargers have a lot of young players on defense who have grown up a lot over the past four months. Look at how much Phillips, Cromartie, and Castillo have developed over the course of this season. Rookie Eric Weddle is a much different player than he was back in September, as he's acclimated himself to the NFL (as witnessed by last week's performance).
The Chargers started 1-3 back in September. If they continued to be the same team, they would not have won 11 games and thus finished the season with a record of 10-2.
The Jacksonville Jaguars are not a better team than San Diego. San Diego's quarterback, offensive line, tight end, running back, and receivers are all better than Jacksonville's. San Diego's defense is also superior to the Jacksonville defense.
I firmly expect the Patriots to win (which I stated in my previous post), but San Diego will be playing hard and I expect a very physical game.