A full system that started from scratch - we got rid of the BOSE amp, replacing it with a MOST25 DA-G2 optical converter and Match UP 6DSP amplifier for pure sound. We have completely re-designed the purpose of the factory doors by using Focal BAM soundproofing on both the inside door panel and outer door panel, effectively creating a fully airtight subwoofer enlosure with an absolute minimum of vibrations. Helix Ci3 speakers and Ci5 subwoofers - possible to change to Focal K2 powers as well. This is our signature Porsche upgrade solution that we’ve done on many 911 and other Porsche models - absolutely loved by Sydney Porsche owners