I found it, here is the turbo V12 Toyota guy
http://www.peachparts.com/shopforum/performance-paddock/288708-190e-sportline-project-now-v12-gt4088r-t56-14.html
Also have a look at this.
M120 V12 Kit Car finally runs.
And there is someone on out list that inserted the M120 into a R107 so do a search for that.
Something to think of on the MB V12 , it was quickly introduced to take a run at BMW and provide the smoothness that a V 12 offers so I wonder if development was cut short. I don't think that just going to an aftermarket FI system is going to cure all ills, but I do expect the stock MB system to be tuned more towards squishy luxury performance.
Frustratingly, the M104 that is the basis for the M120 seems to do pretty well thought is a bit soft below 2,500 RPM making it curious why the M120 is considered a RPM dog.
The Zonda engine is AMG tuned so there could be some hope.
At some point I'll get going on my R129 track day car project, I had dismissed the M120 due to weight an am going to stick with a 3.2 M104.
Is the early 2000's twin turbo MB V12 a M120 or something different? This might be a more direct route.