The Great Catalytic Converter Mystery - 2007 Forester

[pianoman52]

I desperately need a new rear catalytic converter on my 2007 Forester. The only problem is the one currently on my car has a port for an O2 sensor, which none of the catalytic converters being sold have. I've ordered two different ones and while they "fit" there's no where for the O2 sensor to go and it obviously throws a code right away. At one point the engine had been replaced. Kinda a big deal, I also don't know which engine was put in, but I'm assuming something similar as it's interfaced with the car;s computer fairly well. I've look at models of Catalytic converters a few years on either side of my car, but nothing seems to have the O2 port. Any advice on how to find a replacement part that fits? Perhaps I just buy one without the port and have a welder put one in? Open to suggestions.

I've made a little video of the issue, you can watch here. It's a fun 52 seconds