from the article:
One prototype that was testing those engines in Porsche's home town of Stuttgart yesterday night got involved in a minor accident that will still put it out of commission for a couple of weeks.
I'm pretty sure these were turbo, and I'm pretty sure they nailed the exhaust sound. I made eye contact with the driver and he knew that I knew that these were going on the Internet quickly. They were stuck in Embarcadero traffic so I got a good look.