Seems to be quite a split of opinions here.
I'm certainly not a Luddite - my house & car are both full of electronic gadgets & gizmos that I couldn't possibly do without now. Whereas the avionics & engine in a PA28 are 50's/60's technology at best.
I just was not of the opinion that the electric system currently fitted to the a/c was sufficiently reliable to run the FADEC. I note that the SMA diesel engine (which is JAR certified), although FADEC controlled, can be operated manually in the event of total electrical failure.
Sensible : The Wilkshe diesel has mounting kits for a RV9/9A & Europa XS. Although not sure whether you could class either as affordable!
Ninja : take your point about Carb ice etc, but that is something I, as a pilot, can control. Whereas there's not much I can do with the electrics. Would also appreciate Ghengis's comments on this topic.
BPF : Agree FADEC is a desirable advance in principle, but surely a/c electrical systems need similar advanced designs for safety purposes.