mine did this when i got it more so when it was raining it wold judder when i turned the car ater i changed my breaks it went away, and the noise you get on full lock someone told me it a comen fault on the mk3's but that as gone on mine a well .
Nic
I think mine was definitley the belt slipping as everything seems fine now (fingers crossed) and i also had all of the brakes replaced a couple of months ago, so can't be them.
cheers anyway