Alpine - SPC-300A3 Premium Alpine Sound System for Audi A3, S3, RS3
For Audi A3 8PA Subwoofer Housing 20 CM 8 Inch Woofer Space-Saving Boot 4047442079405 | eBay
How to fit and install power and RCA cables in your Audi A3 8L - YouTube
M.A.P Audio & Customs - Custom made fiberglass 8" subwoofer enclosure for an audi a3 8v. This was hand made with mdf rings and support braces. It was then fiberglass and covered
Upgrading Audi A3 OEM Subwoofer with aftermarket 8" JBL woofer and DS18 Candy Amp in stock location. - YouTube
Audi A3 2003 Onwards JL Audio 8" 150 Watts Car Subwoofer Custom Bass Box Kit