I personally like the sound of a 2-stroke diesel - one of the types of engines that died out due to their much higher emissions: https://www.youtube.com/watch?v=mkH9QRaQJM0
Maybe combine with the sensors of a driverless car -- anytime some jerk is approaching from behind at a reckless speed, play the TIE fighter noise adjusted to the circumstances of his relative speed and approach vector. You'll hear the Doppler as he overtakes and then cuts you off. If you're going to pipe engine noise into the compartment, at least make it useful.