Here's a new twist on this...
The S-54 came in the Z3 in 2001 and 2002 models and has 6 seperate throttle bodies as it's a real BMW motorsports motor unlike the S-52 pretend motorsports motor... Does this mean that I can use the S54 ITB's on my M-50 motor build? Just floating an idea out there for my next motor build.
I think not. Block and head must match, and the stock intake manifold must be used. The ITB's on the S54 did not come on the M50, so if you want to use them, I think you would have to use the entire S54 block crank and head as well. Which means you would have to run at 3520#.