DK Engineering F40 User's Guide.

What is the partnumber of the ORIGINAL Exhaust of your car?
Cat Cars have the inletpipes of the silencer orianted as a triangle. NON Cat is one next to each other. As Ferrari had big time investet into developing the silencers, I highly doubt, they would have put a CAT Exhaust on a NON Cat Car. Especially, as you would need different pipes between the Turbos and the Silencer than they already produced for the NON Cat Cars. Like the Testpipes you can buy from Tubi etc...

You can not use the NON CAT Pipes and a CAT Silencer together.

 

Undriveable? One of the magical things I discovered about the F40 is the lack of wind buffeting with the windows open. I've never turned on the AC.

 

unfortunately the car came to me 13 years ago with a tubi already installed and WITHOUT the original exhaust.

the AC works ok, but cant really keep up with the heat in texas in summer

 

I managed to stumble across a tidbit of information, or rather a claim from a dealer, relevant to this discussion. Martini Garage in Germany listed F40 #84474 in ~2020, claiming it was the first catalyzed F40 built. I don't know if that's true or not, but regardless, this is a cat car earlier than multiple non-cat cars I've seen (by chassis #).

https://www.martini-racing.com/en/produkt/ferrari-f40-16/

It seems impossible at this point for the non-cat to cat transition to be clean cut by chassis number. Perhaps it's clean by assembly number?