Sweeper, please be aware that the term 'base audio" is being misused in this thread. The US is probably not going to see base Stereo - just HiFi and Top HiFi/"harman/kardon". The base Stereo system is not what the OP in the thread is working with.
Musicar Certified audio upgrades
OE-Look Enclosures for F10/F30/F32/F22/etc
Add-A-Sub and Full-Bass Packages
Full Cabin 3W and 4W Upgrades
F10 Level Three Add-A-Sub