Is there anybody besides me worried about the Cowboys defense?

I am a big Dallas Cowboy fan and although there offense with Tony Romo, Terrell Owens, witten and everyone else has been terrific there defense has not been that great. They gave up 400 yards to Detroit on Sunday and they barely won the game. Detroit was going up and down the field with ease, and I am worried about there defense. And this is not the first time that the defense has not played great. I think that the Cowboys are the best team in the NFC and should go to the Super Bowl, but do you really think they can beat either New England or the Colts. I would like to hear from other Cowboy fans or just football fans in general. Thanks