Although mine is a gs , I had the same issue that sounded like the front but was the back discs and the rust in the groove causing the noise, removal and a good clean up ensued wire brush, flat bladed screw driver , and few micrometers ground off back plate with flap disc cured problem, which is shown in the excellent picture shown here in this thread, my front end braking judder was virtually cured with a set of front lower no.2 control arms a new set of mtec discs, and a set of unimax ebc brake discs which are very good at bedding in discs