Hmm. Not too sure about forester but I recently installed some 06 wrx seats in mine with only having to swap the buckles. They sit a bit taller but in a better visibility type way. My head doesn't hit the roof or anything (I am 6'2").
Are forester seats way taller then that?
Maybe find some wrx rails? Ha. I looked at swapping with the OE outback seats but I don't think the driver seat will swap based on the height adjustment mechanism.