As far as the wrecks go they both have had a major wreck at the hands of the other. Once they were even they should have dropped it, and kept their distance from each other from here out.
The thing that I don't get is why Carl(or any other full time Cup driver) even runs in NNS full time. He's an accomplished driver in the top echelon of the league, there is no reason for him(or any other full time Cup driver) to continue racing Nationwide on a full time basis. I understand a fill in spot here and there, but not full time - there are plenty of drivers out there. I look at the NNS as a developmental series for drivers on their way to Cup - not for Cup drivers that feel the need to try and dominate lesser drivers.
NASCAR should look into modifying the NNS points system for full-time Cup drivers that race NNS to make it less appealing to them.