found a useful website with details
not an english website by nature
http://www.ffp.fi/index.php?mid=2&pid=24
first off:
bosch CIS fuel distributor flow rates
http://www.ffp.fi/index.php?mid=2&pid=104
Bosch K-Jetronic Fuel Distributor productivity
type cm3/min bar liter/h lambda
0 438 100 013 276 5.9-6.4 150 no
0 438 100 016 276 5.9-6.4 150 no
0 438 100 037 276 5.7-6.4 150 no
0 438 100 047 256 5.5-6.2 140 no
0 438 100 048 220 5.5-6.2 140 yes
0 438 100 076 208 4.5-5.2 120 yes
0 438 100 093 272 5.2-5.9 140 no
0 438 100 094 236 5.2-5.9 140 no
0 438 100 096 270 5.5-6.2 140 no
0 438 100 098 204 5.6-6.3 140 no
0 438 100 109 202 4.8-5.5 140 yes
0 438 100 114 236 5.2-5.9 140 yes
0 438 100 115 248 5.2-5.9 140 no
0 438 100 123 200 5.6-6.3 140 yes
0 438 100 144 258 5.9-6.6 160 yes
0 438 100 145 262 6.1-6.8 140 yes
0 438 100 147 202 5.6-6.3 140 yes
0 438 100 153 202 6.1-6.2 140 yes
next, VW part numbering system
http://www.ffp.fi/index.php?mid=2&pid=140
Each part number is composed of nine numbers in three groups,
followed optionally with a letter suffix:
vvv ggg ppp suffix
Vehicle type (vvv):
155 = Convertible
171 = Golf I
161 = Jetta I
165 = Jetta II
191 = Golf
261 = 16V GTI
531 = Scirocco I
535 = Scirocco II
Primary index (ggg):
100-199 = Engine/Cooling/Clutch
200-299 = Exhaust, Fuel Tank
300-399 = Transmission/Transaxle
400-499 = Front Axle/Suspension
500-599 = Rear Axle
600-699 = Brake
700-799 = Cables, Bumpers and Foot control
800-899 = Body/Interior
900-999 = Electrical, ignition, fuel injection
Individual Part Number (ppp):
000-999 = Individual part
The primary index and the part number are the most important numbers because many of the cars share the same parts. So do not be surprised to see a 171-Rabbit type part in a Jetta.
Note that some part numbers are exclusively related to certain parts of the car.
For example, vvv = 020 are related to the transmission.