TBH, if Detroit beats the Bears tomorrow, I won't even consider it an upset. Jahvid Best is very good as long as he keeps concussions to a minimum, talk out of Lions camp is Stafford has been fantastic, Megatron is Megatron, and Suh/Vanden Bosch is dangerous. Luckily, they haven't gotten to fixing their horrible secondary, yet.
If the OL plays like they did in preseason, Vanden Bosch and Suh will both get to Cutler 2+ times. However, I can see Cutler throwing for 250+ yards and 3 TD's. The rest will be up to the Bears horrible secondary, then.