go for the sti, mechanically theres nothing in it between a bugeye or blobeye sti, its all down to looks
although i should probably ask what youve got just now and what youl be using the car for?
my thinking for getting an sti was that the money saved buying a wrx would soon be gobbled up by bigger spoiler, better brakes, more power which you get standard with the sti plus nicer interior,6 speed gearbox, better handling.
although having said that the wrx is still a very good car and a bit softer,easier to live with every day - either one youl love them to bits as long as you pick a good one!