This came off my 1984 bmw 533i when i upgrade from motronic 1.0 to motronic 1.3. Motronic 1.0 requires a 2.5 bar fuel pressure regulator where as motronic 1.3 requires a 3.0 bar fuel pressure regulator.
Was working when I removed it. OEM part number is 13531711540.
$40 shipped