As per title, what are the thoughts on installing decent, upgarded speaker components into 8L S3? I dont want to alter anything externally i.e. no cutting out of trim. I find the factory BOSE sound system to be quite poor. Current set up is BOSE with Concert CD head unit (off top of me yud) with 6 CD changer in the boot (and BNS satnav if that makes a difference).