Update - just got my car back a little while ago and now it's smooth as butter
! No clunk between accel and regen and it doesn't even make those whining noises when you floor it, totally silent no matter what you're doing with the accelerator. Even when my car was brand new it made those electrical whining noises when you floored it, not anymore. I'm very impressed!!
On a side note, I noticed the paperwork says they replaced the drive unit with a new one. I asked when they were dropping it off if that means new-new or refurbished-new, he said new-new and that they don't install refurb'd drive units.
I was also impressed at all the other things they did while it was in, things I didn't even know to ask for. For example, they found in the log files that the powertrain pump had faulted multiple times in the past month so they went ahead and replaced it with a new pump. They also "checked and trimmed both rear arch liners", not sure what those are yet but glad they trimmed them
Also mentioned in the work order was installing an updated motor mount. I've read speculation in other threads that the noise problems developing in some of the drive units are a result of the motor mounts, so I'm crossing my fingers this fixes the problem permanently! I also requested they install the titanium underbody shield which they did.
Overall it was a fantastic service experience, I even got to drive a S60 loaner for a couple days (what a difference!) and my car came back all clean and shiny. While some may argue that a DU problem in less than 10k miles is unacceptable, I feel that if the customer is taken well care of and not inconvenienced by the problem then it's no big deal, stuff happens! I was never left stranded as the problem was only a noise and the service experience was amazing and no inconvenience whatsoever.