Thanks for the instructions - just did this myself and it worked great. Took 40mins - 1 hour (lack of experience ) The hoses are really difficult to get off of the old fuel filter, but using a large flathead screwdriver worked well. There was very little pressure in the fuel lines when removing the tubes after doing procedure (unplugging the green/white connection, then running the car until it died). I noticed an immediate reduction in the hesitation of my WRX, especially during 2nd gear hard throttle accelerations. I have about 29,400 miles on my '04 WRX wagon.
Something that made it substationally easier to get off for me was to take a pair of pliers wrapped in a rag and crush the raised part at the end of the lines. I did that and the lines slipped right off. no screw driver or anything.