If you are the first owner of the car and the sensors have never been replaced, at that mileage I would replace all four.

The prices you listed are somewhat low for non-generic Bosch, and about right for generic Bosch.

If you want to get sensors with the connectors already attached, first get under the car and check the color of each connector. Depending on the car, all four connectors could be different. The replacements must have the correct colors.

Generic sensors are OK if you're sure you can splice the wires correctly, solder them, and heat-shrink insulation over them. Personally I prefer those with connectors already attached.

Thanks for the reply. I tried to see the sensor but is hidden well, I'll need to get the car up on a lift to see under it.

I did let the car warm up a lot, then drove it and then shut it down, and restarted and the light went off. Regardless, I agree with you that I should replace the O2 sensors (fronts) as it has over a 100K miles.
Mark

Anyone use Beck/Arnley 156-8400 sensors? They are listed for many MB models that use a 4 wire 02 sensor.

http://www.beckarnley.com/