Do after market o2 sensors work on 97 986?
 

Any recommendations?

I've tried to use them in the past, and I've had spotty results with them. I typically recommend using the factory sensors. If you read the Bosch documentation, you will see that the sensors are waterproof, and supposedly gather their reference air signal through the cabling that runs to the sensor. So, if you cut and solder the cabling, you may screw up the reference signal. I documented this in my book...

-Wayne

I have had my bosch buildable sensors in the car for about 20k miles now and have not one issue. :)

I just bought a Porsche OEM O2 sensor for $160 and I could have gotten a generic 4 wire Bosch thimble type (in about 75% of cars on the road) from Napa for +\- $65 and soldered the wires to the old connector but I was on my way to a DE and did not have my soldering iron so I opted to spend the extra for convenience.

Once I was at the DE the wire was too short for the OEM (I have headers) so I ended up cutting the pigtail off the old one and twisting the wires together with the new sensor. Needless to say I could have saved the $90 odd bucks and gotten the generic part and it would have worked perfectly since I ended up having to cut the wires anyway.