Im new here so first of all hello to everyone.

Right I have just bought a RST Cabriolet EFI on a G plate.
Since getting it home I have been poking around and seeing whats what with the car and come across the ECU which is a 1afa ecu.
Correct me if im wrong but this is from an xr2i / xr3i???
So how can it be running properly? It runs fine, but I dont understand how if its running xr management? Has anyone else come accross this before?
I have just ordered an OFAC ECU to replace it, because I would rather have it running on the correct management, But as I said, I just cant see how it can run fine on XR management.
Im just trying to get hold of an OFAC map sensor now so if anyone has one, let me know.