[emhtuning]

p/n: 6512 9393181
The amplifier uses most.

ma apologies for misleading information I have posted earlier ,, I was lazy to look at ETK , I only looked for a picture of the amp to see the ports .. 

now after looking at ETK , this part number actually is perfect match for F10 HK 688 option .
so basically remove the old VO of the sound system ( 676 in your case ) , add 688 to the FA ,, and code at least CIC and amp ( maybe KOMBI too ) .