what exactly is an M-8? I just purchased a 2010 E60 2 days ago with a HiFi sound system. Sound is okay. I have test driven another E60 with the L7 sound system and does sound much better. Is this M-8 an upgrade to L7 sound?
Although i'm very familiar with upgrading to aftermarket sound systems. I want to try and keep thing as OEM as possible. Avoiding the extra Amps and boxes in the trunk.