They have a top 10 run d and a pass d that is somewhere between the 16th and 30th worst. The thing with their defense is it is masked by peyton's play. He spends so much time on the field, that the other offenses struggle to find rythem and are often playing from a few scores behind. This makes their run D stats amazing, but thats because in almost every game no one tried to run against them. they have 3 good linebackers and 2 good linemen, one aging star corner, and serviceable starters around.
So what does all that mean? It means if you can run the ball down their throat for long scoring drives, its going to be a close game.
Also this is the best pass rush they will have faced. Peyton doesnt like pressure.