Originally Posted by acumenhokie
I've never changed the oil on an STi before but I imagine you pull the oil plug, drain the oil, pull the filter, put a bead of oil around the new filter, put it on, put drain plug back in, fill with oil, drink a beer.
The biggest difference is the splash guard you "should" remove first. you could change the oil without removing it, but it would probably get oil all over it when you took off the filter.
other than that added step, you got it on the nose