Thanks for the description of codes Nathan. God, I hope they didn't screw up the rear O2 sensor but I don't see how they could have (and because I watched them work). The work they had to do wasn't that close to that last O2 sensor. Originally I thought it was because of the 7 turns I did on the wastegate rod so I went and lengthened it before I cleared the codes. But after doing that and driving for only a day, the same codes re-appeared. But I'm pretty sure it's related to the exhaust system seeing that everything was fine before I went and put back in the stock muffler.

Thanks for your help anyway, now if only someone can help me figure out why I'm seeing these codes and how to get rid of them for good....