The Lions, more than most any other team, are going to be in serious cap trouble with Calvin, Stafford and Suh's 2nd contracts. The problem with these three is that they were all 1st or 2nd overall picks under the final 3-4 years of the old salary system. Their first contracts are all double what a #1 pick would get now and their 2nd contracts will only go up from there.
The result is that they will be hard pressed to sign their lesser players, like Avril, to second contracts, let alone go after quality free agents to fill needs in the secondary, linebacker and o-line. It will be even worse as they attempt to sign Calvin, Stafford and Suh. Stafford is a QB, so it's automatic that he gets top $$. IMO, Calvin and Suh are not the kind of players who will give a hometown discount to alleviate cap space and help the team to sign better players. I believe both will expect to get paid as the #1 at their position, regardless of what it means to the cap. And while it's their right and Calvin, in particular, deserves everything he can get, their contracts will prevent the Lions from taking the next step.
In the end, I believe the Lions will sign Calvin and Stafford and will be forced to let Suh go. I think the Lions front office is very shrewd, but they will need to get very lucky with later round draft picks and older FAs to have a shot at a conference championship or Superbowl. The old salary system will hamper the Lions for sometime.