I've got a bog standard set-up in my S3, although it does have a CD changer. I'm looking to improve it but don't really know where to start. Does the standard head unit have a pre-out so I could install an amp and new speakers? Ideally I would change the head unit but don't want it to stick out like a sore thumb if the fascia panels don't match up. What have you guys done if anything and what would you recommend?