If I were a cop id be sitting near a round-about fining a million people a day for not indicating properly, till they learnt.
in any case wrx's are always capable of 'going too fast' relative to most cars, and that isn't what they got you for, they were just trying to get you to admit that you were speeding.
But you certainly failed the attitude test by the sounds of it - just play it cool or if your in a bad mood don't stop for cops :P Nothing like a good high speed chase to get the blood pumping.