Subaru Build Update and EPA Comment

I'm re-rebuilding the Subaru since last time I had a bit of porcelain or burnt valve tear up a sleeve. I have a lot of money in parts, and part of those are parts was buying a cat to weld in to the downpipe (rotated turbo setup on a Subaru). And I worry about putting this all together and finishing it because, yeah, even though I'm trying to be clean here, it won't really be legal according to my reading of the EPA's change in enforcement because it's not the same cat, and it's not the same exhaust.

It really does suck that SO many others couldn't play nicely. But, a rotten apple spoils the whole bunch.

Another add to my worries is that having Dave / That Dude in Blue as the counsel for my effort at keeping my build going is not the help I was looking for. His argument is reductive at best, and I can only think to myself that others in my position would look at that argument as terribly as I do.