Like a ringtone for your car

So you’ve bought a new Ford Mustang and you want to hear a perfect deep-throated roar as you punch the gas and pull away from that Chevy Camaro. There’s an app for that.
Roush Performance’s Active Exhaust lets an Apple iPhone or iPad customize a Mustang’s sound and save the settings on those devices. It’s available for 2015 Mustangs with Roush’s Quad Tip exhaust system.
The system comes with three preloaded exhaust modes as well as the ability to create a custom sound. Touring is a quieter setting for neighborhood cruising. Sport is louder at lower speeds and less noisy in normal city driving. Track, for off-street use, bypasses the muffler for a full, unrestricted tone.

When I first read the headline, I thought Ford was making an all-electric Mustang, and that the engine noise would be synthetic. Electric cars are so quiet some think it's a safety problem as pedestrians, cyclists, and even other drivers often can't hear them approaching.