I haven't done it yet. Too busy and the light mostly stays off. I did verify that there are four sensors, two (barely) visible from under the hood on the exhaust manifold, and two under the car after the cats. None of them look that easy to get to.
The exhaust system itself is good quality stainless steel, but some of the fasteners are another issue. The flanges and bolts that connect the back of the cats to the rest of the exhaust are very rusty. If any of the exhaust system needs to be taken apart to get to things, this is not going to be a fun job.
So being lazy and over-committed, I am putting it off.
