So I was attempting to lower the exhaust to install my DSS driveshaft and one of the bolts on the cats locked up half way out and would no longer turn. I think the threads are destroyed as the nut is now stuck about 1/16" off of being seated on the cat. I realized I could do the install by threading the driveshaft from the rear afterwards. Driveshaft is in and good to go but now one of the two bolts is not torqued down on the driver side cat. I didn't hear any exhaust leak when I drove the car afterwards but I know it will leak. I will attempt to soak it with some liquid wrench on Monday but other than that I think I will just end up taking it to the dealership to have the old stud pressed out and a new one put in. I don't have the tools to press out the old stud. If anyone has any ideas on what can be done please share.