I have replaced just the voltage regulator before, since the alternator seemed otherwise OK (not squealing or grinding sounds when I turned the pulley).? Autohaus AZ had the voltage regulator which included the brushes, etc for around $75 at the time.? You can swap out the voltage regulator with the alternator in place, so it is pretty easy to do. (This is on a VR6 model but I would think that the regulator is at least available for your model, access may be another story all together).? This is pretty common preventative maintenance on the 1.8T motor also.