E90/E91 Upgrades

Full-Cabin Upgrades are wonderfully musical sound systems, using stock locations.
“Four-way” Full-Cabin systems include a true trunk subwoofer, and use
the underseat woofers as dedicated midbass drivers.

Add-A-Sub packages add a high-performance 10-inch subwoofer in our OE-Look Enclosure.

Full-Bass Upgrades add a high-performance 10-inch trunk subwoofer, and improve midbass performance.