I had the exact same thing before I put coilies on my mk4, changed loads of stuff till I found the problem was the shock itself, it used to creak a lot when parking (turning left to right) just do a quick check... Open your bonnet push down on 1 side of the cars wing really hard (don't bounce just put some weight on it) and do it on the Inside of the wing not on the actual paint, and then put your fingers/hands under the wing and gently lift the car upwards try it a few times... Slow / gently / bit faster and see if you hear the creaking... Had this on an Audi tts aswell and those shocks are silly expensive, us GTI peeps are ok lol :-) hope you find your problem I hate those annoying noises you can't find!