Ok, some research has found these facts:
Golf Syncro 1.8 litre (1P)
88-91
Bosch Digifant II
0 261 200 295
037 906 022 FH
XEVD22FH
Golf Syncro 1.8 litre (1P)
88-91
Bosch Digifant II
0 261 200 294
037 906 022 M
XEVD22M
Golf GTi 1.8 litre 8 Valve (PF)
87-89
Bosch Digifant II
0 261 200 296
0 261 200 297
037 906 022 BB
XEVD22BB
Golf GTi 1.8 litre 8 Valve (PB)
88-89
KEN Digifant II
037 906 022 BC
XEVD22BC
Golf GTi 1.8 litre 8 Valve (PB)
88-90
KEN Digifant II
037 906 022 AN
XEVD22AN
Golf GTi 1.8 litre 8 Valve (PB)
88-90
KEN Digifant II
5WP 4 034
037 906 022 DC
XEVD22DC
Golf GTi 1.8 litre 8 Valve
88-90
KEN Digifant II
037 906 022 E
XEVD22E
Golf GTi 1.8 litre 8 Valve
89-90
Siemens Digifant II
5WP 4 062
037 906 022 EN
XEVD22EN
Golf GTi 1.8 litre 8 Valve
88-90
KEN Digifant II
037 906 022 F
XEVD22F
Golf GTi 1.8 litre 8 Valve (PB)
88-90
KEN Digifant II
5WP 4 086
037 906 022 FJ
XEVD22FJ
Golf GTi 1.8 litre 8 Valve (PB)
90 on
Bosch Digifant II
0 261 200 298
0 261 200 299
037 906 022 N
XEVD22N
Golf GTi 1.8 litre 8 Valve (PB)
90 on
Bosch Digifant II
0 261 200 298
037 906 022 DB
XEVD22DB
So this explains a bit about the ECUs and where they go and why. Age revisions seems the first variance, but whats the difference between PB and PF engines?