i have and a3 se, had it lowered 30mm (im sure it was more though) but the front sat about 10mm higher than i wanted so got my self a
set of h&R 45-50mm lowering springs.
i did the front and i would say it might have gone down a small amount, i fitted the rears and after fitting, the rear end looked back at standard (would say it was a good inch higher) now i know they say the will settle but not that much, so fitted old lowering springs back on,
have to say you can feel the improvement on the front though.