Thanks for a great DIY article.
Does anybody have any experience with the cheapest hifi option called "Business CD' which is only available in Europe. I have this system on my E91 and it consists of 4" koaxial in the doors. No external amp, no sub, no tweeter etc.
I am planning to add a sub in the trunk and would like to know if this wire diagram somehow could help me connect a HI/LOW converter.
Thanks in advance!