Can The Vikings Be Stopped?

It seemed when Brett Favre signed with the Minnesota Vikings, many people were still skeptical whether or not he could have an impact.
Well, from watching this past weekend's Lions-Vikings game live, I really don't think there will be a team in the NFC that can compete with the Vikes.
Honestly, we all knew what we would get from Adrian Peterson. He is atonishing to watch in person by the way. We knew the predictions. He's going for 2000. He will likely be the MVP. The moves this guy make are unbelievable.
But, the addition of Favre brought a passing game with it. Sure, many watched as Brett collapsed late last season. The 22 interceptions caused a lot of football fans to doubt whether or not the signing of Favre would even improve the quarterback situation in Minny. How do those people feel now?
Favre was 23 of 27 on Sunday, for only 155 yards and two TDs. Some say he can't throw the ball downfield anymore. But, the good part is that he hasn't had to. With AP running, and Favre making manageable throws, the Vikings could be tough to beat in the NFC.
Another factor is the defence. It is much better than last year. They still have the huge defensive line, but the players that impressed me were the linebackers. Chad Greenway is a phenomenal player, as evidenced by his two interception, one fumble recovery day against Detroit.
The secondary also did a great job shutting down Calvin Johnson (for the most part). The line still got pressure from somewhere other than Jared Allen as well.
If this all continues (and I know it was Detroit), the Vikes could be the team to beat in the NFC North. They have a huge matchup this week against San Francisco. (Did I just say "huge game" and "San Francisco" in the same sentence...wow)