my stock O2 sensors are stuck in there and I cant get them off to save my life. I borrowed a o2 socket set from the parts store, and drove around to pre-heat the pipes. I even tried PB blaster, which I dont think would do anything anyways, just for good measure. Any other tricks that you would recommend?

 

Try it with the engine cold?

 

Try heating the local part of the pipe with a torch, that way the outside should expand before the insert and give you a better chance.