Got a Mk4 2.0l 8v and wish to fit Bosch EV1 injectors like the 440cc green tops? That's entirely doable so long as you make the bottom o-ring setup compatible. Use this inexpensive kit to convert all four injectors in minutes.
a) Remove pintle cap, o-ring, and plastic spacer from new injectors.
b) Replace with two provided o-rings from kit.
c) Attach new pintle cap.
(Note: Video shows single o-ring replacement, but process is otherwise identical.)
4x sets of 3 o-rings each (1x top + 2x bottom)
4x pintle caps