Just installed a Pioneer TS-WX300A, so far so good, couldn't get it connected to the radio so just tapped into the back speaker. All in all it was about 3/4 hour job
Pioneer TS-WX300A 30cm Powered Active Subwoofer with Class-D built-In Amplifier (1300 W) Single Voice Coil. , Black : Amazon.co.uk: Electronics & Photo