check out this place in san carlos:
www.soundwaveme.com
Talk to Mark about what you need, he is kind of the front end guy. Otherwise talk to Dave, he is the main installer - been doing it for like 30 years maybe more.
They work on all high end vehicles and I am sure they have run into the same situation you have. I will try and give him a call and ask about it if you want me to. Just let me know exactly what you need. I go to them for all of my audio hardware