I wish I could be sure it is just the voltage regulator but so far no one can confirm this - have sourced one from the states at $100 delivered - have read all the woes on this site from people just changing the VR and then still having to change the alternator.
Have also sourced an Alternator in Aus for $900 but they are quoting it as 180 amps? I am waiting on a response from them re: brand, bosch or valeo - according to RealOEM mine is a Valeo 170 amp so not sure if the Bosch 180 amp is a compatible unit.
Did you remove the front fan etc to access yours or do it from underneath - there is a "how to" on here somewhere but its for the earlier watercooled unit.
cheers

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X5 4.4i 2006 sports package, Titanium silver, Sports exhaust with Xpipe, Limo tint, 20" wheels 168's (Black), 25mm H&R wheel spacers& arch flares all round - Loud........

Work in progress -:
Replace BMW Ipod system with DICE - installed but no sound yet??