I haven't had a chance to listen to the Bluetec, but the CDI that I test drove (an '06 model) still had a recognizable diesel clatter at idle when standing in front of the car, especially with the hood up. In fact my OM606 isn't much louder. I don't need my diesel cars to sound like a Cummins truck, but I do need at least some diesel clatter at idle when standing outside, otherwise I might as well buy a gasser.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL