What's the Gas + EV (Harvester) version going to sound like? Fake exhaust sound?

[JCintheSJs]

Given that it's basically an EV with a gas powered generator in it somewhere, what's it going to sound like driving on of these? I assume it's not going to sound like a typical generator running. Are they going to pipe in fake ICE exhaust noise? Something else?

 

[Noplacelikeloam]

I hope it only kicks in above 30mph or so. Otherwise we are all going to look like we are driving lawn mowers.