I usually have the car in stealth mode, so it's quiet. If you turn the sound on and start the car, it kind of sounds like the Batmobile from the '60s TV show. I think that's because part of the sound is a tweaked recording from the Chrysler turbine car.
The sound level inside and outside changes depending on the drive mode you select. From lowest sound to loudest, Auto, Sport, Track, and Drag mode. There's also a custom mode and a rain/snow mode.
Drag mode is really, really loud.
One thing that is missing is changing the engine sound to mimic transmission shifts. It just does one long pull as you accelerate, since the gear box only has one ratio.
It is ridiculous fun.