My experience with NGK/NTK O2 sensors on the Q45 (left vs. right) is the different part numbers represent different cable lengths. While the part numbers and cable lengths differ, the sensor element part is the same.
For discussion purposes when you are in a pinch, is the O2 sensor (element) the same for the rear sensor (Sensor 2) as the front sensors for a Fed Spec model? If yes, the NTK part number is based on the cable length (and grommet) difference.
Also note Greg has posted some GREAT instructions about changing the rear O2 sensor at the following URL location.
http://www.nicoclub.com/archives/maxima ... ensor.html
As a side note, I was able to pick up a new NGK/NTK O2 sensor (part # 24630) for $53 and change (with free shipping) at Advance Auto Parts Online by using one of the discount codes from http://www.offers.com.
Now I know what I'll be doing next weekend.
