The problem that sent it in was the charger. I surmise that something about the alternator (or whatever the AC->DC conversion circuit is) failed in one of the dual chargers. I plugged it in at home and it would ramp up to about half speed (I have a 100 amp circuit for it) and then pop up the message that it was "Unable to charge". Charging it at the Supercharger still worked, though. So direct DC charging was unaffected. Also, the loaner charges just fine off the home unit, so it's not the charger itself. In other news, they replaced "the charger located under the rear seat" and I'm getting it back today. YAY!
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As for the loaner, it was a P85 blue/black performance seats, dual charger, (no jumpseats), governed at 80, amazingly hilarious "balloon sound" acceleration with 7k miles on it. So they at least matched the model with the loaner. All in all, the experience was very pleasant; I had the feeling it would take longer just because it took 4 days to set up the appointment to get it picked up.