I installed the same Quantum pump into my 90 G60, Only thing I had to was adjust the angle on the arm the sender gauge is on. The piece that drops down had a slight angle and with the pump locked in place it was pulling the top of the pump over to the left. I used a heat gun to soften it slightly so I could push the whole area over slightl. My tank was full and its currently reading correctly, We will see as the level drops if the gauge continues to read correct.
Pros: reading correctly
Cons: adjust the angle
Vehicle:
Volkswagen