I currently have an 03 TS and the fuel filter needs to be changed fairly often, but at least it's easy to get to :)

On the 05/06 impreza's how often do you have to change the fuel filter? I also heard that it has gotten relocated into the gastank (2.5L NA engine), is it still a do it yourself job or do I now have to bring it into the dealer?

....can be done yourself.....instead of taking 15 minutes....it will take an hour and 15 minutes...much greater risk of borking the job, though.....but once you have done it once...piece of cake ;)

It is essentially like doing a fuel pump replacement....back seat out....access plate off....hoses off....8 little nuts(BEWARE overtorquing them).....pull assy out of tank(BEWARE bending float arm)......change filter.....reverse process...BEWARE gasket at top of assy(can be a PITA).....done.