ok - cabin filter was easy, though i may have messed up my side body molding by accident.
engine filter, i popped the two metal clips, and it doesn't create a big enough gap to pull the filter out. i guess that's why you said remove the air duct. i think i found a video of someone doing it on an older legacy gt, and they removed the duct. should be basically the same right, because the engine hasn't changed much...