Up for sale are some M2 test pipes off of my 2008 350z... Used for about 6 months/~4,000 miles (little over one oil change). I have all the gaskets (although I'm pretty sure its recommended that you get new ones on each install) except 1 of the fronts (iirc) and will send over the hardware I have.

When I pulled the driver's side O2 sensor out it was threaded slightly, you can see in the pic with the cover that its sticking out a little from the housing - you should be able to either die/tap it or power through (preferably with the cap first versus your O2 sensor).

Looking for $80+ship from 28277.