The BMW M135i is a great little car, but like all owners, this guy secretly pined for an M4. So what did he do? Hack the M135i's sound program to make it pump sweet M4 tones into the cabin, of course.
BMW's Active Sound Design program feeds engine noise into the driver's ears by pushing a sweet note through the speakers in the cabin. What this guy did was figure out how to make his sound like an M4 instead of a 1 Series, and voila! Instant supercar.
Engine noise feedback is a common feature among cars these days, with cars from BMW right down to the Focus ST feeding throaty engine sound back through the internal speakers to delight the driver.
Here's what the M135i sounds like normally:
Still impressive, but if you can make your car sound like an M4, you definitely should. [Jalopnik]