Don't even want to know the price of a 2024 vintage oem Diesel catalyst-- Likely more than my entire exhaust system INCLUDING the turbocharger.

 

Stock downpipes from a 2024 BMW M2 G87. 3.0L Twin Turbo. Those are 3" v bands.

 

Good idea

 

I know you guys are talking about diesel cats only because of the location, but don't get the idea of reducing exhaust fumes using one. I found this doing a search, made by artificial intelligence-

Emissions Focus:
Diesel converters are designed to primarily address particulate matter and carbon monoxide, while gasoline converters focus on reducing hydrocarbons, carbon monoxide, and nitrogen oxides