1" line wrench on the filter housing, and a 5/8" line wrench on the fuel line breaks it loose. Then pull fuel line out of the way (it's tight but it CAN be done) and unscrew the filter housing. Be careful not to lose the spring behind the filter or (and this is IMPORTANT) the thin plastic seal that goes around the end of the filter housing (this is the only actual seal for the housing). The seal "clicks" in place on the end of the housing.
IMPORTANT TIP: DO NOT USE TEFLON TAPE ON ANY OF THE THREADS. (line or housing)
The Q-Jet is great when you know how to set it up.
And YES, it DOES matter about the spring missing. That's what keeps the filter seated against the housing. Without the spring, you get no filtering.