I just did the best upgrade for my Model S. As we all know the audio is really missing the low end bass. NVX audio has made a custom Tesla package. It includes 10 inch subwoofer in a nice carpeted enclosure, amplifier, amp wire kit, and bass knob. You can get this installed at custom car stero 713-981-8455 please ask Jonathan about the Tesla Forums discount or mention my name. I can meet up with you if you would like to hear the HUGE difference in sound.