Just a side note since I odn't think anyone mentioned it yet. If you are welding in the bung with the piping on the car, try to find a location where the wideband O2 will be horizontal (worst case) or pointing downwards (don't recall the ideal angles, but use the stock ones as a ball-park). If the O2 is pointing up a) you will remove it quickly on your first speed bump and b) condensation can pool on the sensor leading to poor readings and premature failure.
