Oxygen Sensor
 

Are all oxygen sensons in a 2004 boxster s identical? I need to replace the sensor at bank 1 sensor 1 and I am finding conflict information. On some sites theres only one available (even at the dealer) however on pelican and on ebay there are 2 types - pre and cat with a 30 sterling difference.

by looking at the pelican parts catalog,looks like there is only 1 sensor for your car.
Pelican Parts - Automotive Parts and Accessories - Porsche & BMW
the other two, are for 97-99 and 2000-2002.
if you want to be sure, look at the part number on the sensor you need to replace, and search by that.

Oxygen Sensor
 

After you identify the correct senor via Pelican Parts, go to rockauto and get them dirt cheap.

I paid just over $83.00 each for four for my 99 Boxster earlier this year.

I believe the before and after sensors are different in that the lengths of the connecting cables are different. If you have a lot of miles on the car, buy 2 before and 2 after sensors and replace them all.

According to a competitors site in Arizona, the 2004 S used all the same O2 sensors. It was the only year that did this. I attempted to post the link, but it appears to be blocked.