Well, now that the snow has melted and I had the time to crawl underneath and really take a look at it. The Y-pipe is rusty on the outside, but it's still very serviceable, and definitely NOT the source of the leack that I was having.
The ACTUAL problem turns out to be the PCV line popped off of the flame trap. Not sure how that started causing fumes in the cabin, but it did. It also caused one heck of a odd idle problem. Put it back on, reset the ECU, and we're doing just fine.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.