Hi Harald,
I'm the SI guy.... First point of call I would suggest is the AeroSance FADEC yahoo group - specific FADEC information etc there including 8 builders. There are a number of European based FADECs that I know of, Mark Castle-Smith (UK) and Rene/Aart (Netherlands) being two obvious ones.
Layout and wiring is a key element of the FADEC system - but once it is all working it is REAL smooth and pretty frugal with the fuel.....
Regards,
Carl