Over the break I replaced my old cracked exhaust manifold. Thanks to Honda's one-piece design, that meant replacing the catalytic converter as well. The casting was a flawed design and this is a common failure point. Junkyard cars usually have the cracked manifold as well. I went with the $167 Dorman aftermarket replacement instead of OEM for lower price and (hopefully) a better design. The old cracked manifold. O2 sensor already removed. Heat shield missing when I bought the car. Overnight I soaked everything in Liquid Wrench. Trouble! This nut at the bottom end of the catalytic converter wouldn't come loose. Unsurprising, really, after 16 years. So I unhooked the next joint about 2 feet downstream. This came loose much easier as I replaced the following pipe only 5 years ago. It was a hassle to remove the L-shaped mani-cat-pipe combo - I loosened the front engine splash shield to drop it out the bottom. Once out on the ground, I hammered a socket onto the stuck nut and was able to remove it. Getting good leverage was much easier that way. The new manifold. Everything fit pretty well except for one bracket. A couple spacer washers and that was fine. Both O2 sensors salvaged and reused. Notice that this is a 2-piece design with a bolted joint just below the manifold. All finished, this time WITH a heat shield. Now it's again a CleanMPG machine, instead of just MPG. Performance is no different that I can tell, just a tiny bit less engine noise that only I (the daily driver) would notice.