In all seriousness, I think for minimal cost they could capture sales with this. A big a** bass speaker and a regular speaker near the tail, and possibly a bass speaker pointed inward or otherwise configured as a thing which shakes your car/seat. Normally it would just be off, but a user could configure it to make normal, BMW-ish, racer-ish, mercedes-ish types of engine noise. Hell, you could simulate gear shifting with accompanying tone shifts. Auto makers already artificially tune/augment their engine noises. For people who just have to have the visceral power feeling that comes from the inefficiency/waste of an ICE, just simulate it. It would be amusing to simulate an engine screaming and changing gears have people do ludicrous starts with and without the engine noise. Show a gearhead this "new german supercar" with sounds on, then freak them out by turning it off and saying, kidding it was electric.
Since many jurisdictions are legislating "noisemakers" anyway, just make a good noisemaker and make it a feature. (Disclosure, I would not use such a dumb thing)