colour means nothing on digifants, there are various colours depending on the year of the car. There are no real differences between em, just the older ones were superceeded by new bosch parts as bosch stopped making the old ones. Here are 3 different types all listed for the MK2 digifant, depending on the year. Even the lowest rated cc/min injector is more than enough for a MK2 digifant car

Volkswagen MK2 digifant = 191.8cc/min, Bosch 0 280 150 757, VW 037 906 031A
Volkswagen MK2 digifant = 197cc/min, Bosch 0 280 150 903
Volkswagen MK2 digifant = 218.1cc/min?, Bosch 0 280 150 902, VW 037 906 031C