Vpas12st 12" Active Spare Tyre Subwoofer 150W Rms - Audio | Hyper Drive
1pcs Car Active Under Spare Tire Subwoofer Built-in Power Amplifier Max 380w Car Trunk Tire Audio Pure Bass Sub Woofer Speaker - AliExpress
JBL BassPro Hub | 11" (279mm) Spare tire subwoofer with built-in 200W RMS amplifier with remote control.
Nakamichi 15" 1200W Spare Tyre Active Subwoofer NBF150A - Nakamichi SA
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