S85 - VIN P50357, delivered 9/27/14, 15,600 miles so far. So I started hearing a new sound on acceleration Monday after Thanksgiving. Had it checked out last weekend (12/5) and it turns out I have the dreaded milling noise. Tech said I'll need a new drive unit and has me scheduled for 12/19 and I leave for Vegas on 12/20. I'm planning on taking the car. From those of you who have had drive units replaced, I was wondering if I should be concerned about doing this one day before my trip. Side note, tech said, "Good thing is, you'll be getting the new drive unit." I'm assuming he's meaning an upgraded, sturdier version of the current one. I didn't realize I had an older iteration of the drive unit. I appreciate the feedback in advance, thanks!