I have been reading about where most ppl have the mounting bung welded for the 02 sensor. Ive read pretty much pre-cat welding is where its been done for the 350z. Just wanna make sure this is fine.

 

well if you have cats then yes, because the wideband would be useless after the cat, if you have test pipes then it can be anywhere on the test pipe, without making much of a difference

 

Thanks i still got the stock exhaust system and will prolly have it for a few months so yeh ill prolly have it welded before the cats

 

Your going to have to remove the cat to install the bung correctly, so why not pick up a set of test pipes and save the time of doing it later.

 

Or...

He could purchase a set which already has extra bungs installed

 

This.

If you're not doing it yourself, you're going to spend the same amount on labor for the removal of the cats, prep work, welding, and to reinstall the cats as you will spend on just buying a set of test pipes with the bungs already pre-fixed, and you can do the cat/test pipe swap yourself.

 

Best idea right there thanks!!