I successfully installed the non-foulers on one test pipe, but the 02 sensor is seized on the other. I tried every wrench I and my neighbors own, nothing worked, it is gradually coming undone but maybe one in every 8 tries it will actually turn. It's getting stripped bad... What do I do?!?

 

when I took out my driver side sensor the threads were trashed from the install...I spent a good 30 mins with my dremmel recutting the threads