OEM 11-20 Volkswagen Spare Tire Mount Subwoofer Soundbox Jetta NEW 000-051-419-B | eBay
JBL BassPro Hub | 11" (279mm) Spare tire subwoofer with built-in 200W RMS amplifier with remote control.
Sennuopu Car Subwoofer Class Ab Power Amplifier Bass Speakers Aluminum Box Active Sub Woofer Install On Spare Tire Audio System - Subwoofers - AliExpress
Best Buy: JBL BassPro Hub 11" Single-Voice-Coil 2-Ohm Subwoofer with Integrated 200W Class D Amplifier Black JBLBASSPROHUBAM
Manufacturer professional wheel spare tire subwoofers sundown audio subwoofer car with 10 inch bass speaker
For those of you who want more bass but don't want to sacrifice your spare tire or hatch space, I highly recommend this spare tire mount subwoofer : r/GolfGTI