Thanks for the response but its all done now but heres a few answers to aid you in your V12 project.
#1
SAFCII = Super Air Flow Converter II
It tricks the MAF to read a higher airflow throughout the rpm range and its highly tunable. Very good thing to have when turbocharging NA cars.
#2
www.startekinfo.com its amazing its $18 to use an entire mercedes benz data base for one day 96 for a week and other stuff. It lets you view basically every part on your car, they have EVERYTHING not just wiring. My subscription just ended but just sign your self up for a day($18) and print off ALL of the wiring diagrams for your V12, thats what i did for my little L6. Its very interesting too and really easy to understand, with all of the diagrams i beginning to figure a way to shut down the pesky ETC on my car. It leaves nothing out in the wiring diagrams and gives you a complete diagnostic(I found that a little late
)
#3
Star Imports is an AWESOME little shop around where i live in Jeffersonville, Indiana. They completely rewired my 86 300e and i mean completely, body electrics and engine electrics. They are a small pack of mercedes gurus. They are tiny but they rival bigger names like Tafel and have much better customer satisfaction. They always seem to be working on sl500's and Sl600's with V12's like yours, no joke. Theres two Sl600's at their shop right now.