nvu

swapped blowers on my 2003 impreza wagon with a 2006 year unit. it looked like the motor is molded into the ducting assembly. i could be wrong though, didn't look too carefully as i already had the entire assembly and didn't need to swap blowers. anyways, to get it off of the car, I had to remove the nut holding the white upper piece to the dash. (it's hidden under the wiring loom). then when all nuts are off, the white piece is held to the black piece via plastic tabs. you should be able to feel them and unclip them by hand. after that you should be able to pull the lower assembly out.

Quick search on ebay shows that it's the same bearing for 1993-2007 imprezas. (non sti) http://www.ebay.com/sch/i.html?_odkw=wheel+bearing+impreza&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xfront+wheel+bearing+impreza.TRS1&_nkw=front+wheel+bearing+impreza&_sacat=0 The manual likely is trying to say that the bearing isn't reusable. Once you press it out of the hub, you've already ruined it. Press in a new one and you're good to go. You'll probably need the grease seals as those easily get ruined when pressing out the old bearing.

If you suspect the fan motor, I'd remove the glovebox to get to the fan motor connector. Test for voltage on there. If there's voltage, chances are the motor brushes are worn. This happened on my impreza, the fan would intermittently work. Once it started spinning it's good until shut down. I eventually swapped in another blower unit and things were back to normal.