[ctuna]

I think you don't understand how mr12volt works .
It hooks up to the Most and all it's signals go through
the Most this is for both the old version and the new fancy version
for the idrive.

Mr12volt uses the Most bus through the Compact Disk changer port on the original unit
and everything goes through that. You only have to enable the CD port and add the Mr12volt device
to the Most Loop.

You are pretty unclear on what you started out with and what you want to
achieve.

If you have base system and want better stereo the base system is most of the problem.

Toslink would be stupid course of action to take . Mobridge use to make a Most to Toslink translator
I believe and it cost 500 plus and I have never seen anybody use one. I have no idea of the quality
on Avins analog output but the stock BMW stereo's programmed to a Hi Fi output are pretty good.

You have to be able to tune the DSP to get the best out of it. And aftermarket speakers take it to the
next level.