Tuning - Best place for an o2 bung
 

Is the midpipe a descent spot to put an o2 bung? Or is the down pipe a better location?

end of downpipe after it flattens out, make sure to mount the sensor within 15 degrees of vertical

Depends on the type. If self heated, anywhere in the exhaust.

Otherwise not over 3 feet from the turbo/s.