Subwoofer Box as a Spare? Volume Calculations + Build - CarAudioFabrication - YouTube
JBL Basspro Hub - 11" Spare Tire Powered Subwoofer System with 200W Amplifier, Black - Walmart.com
Amazon.com: CERWIN Vega 600W Active Spare Tire Application Subwoofers Series (VPSTX12) : Electronics
Carboutique - Spare Tyre subwoofer from Megaaudio In 400... | Facebook
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
19+) - 2020 - HK System Subwoofer upgrade to Spare Tire Sub? | Subaru Forester Owners Forum