Motec is a choice I made a long time ago and quite pleased with it on the technical aspect, commercial is a bit of a different league and in that respect the whole car is in a different league. Build a 911-RSR 1974 replica some years ago based on a 964 chassis and went all out with standard Porsche parts, i.e. GT3 gearbox, GT3 ABS, 993 GT2 EVO 2 front end and that list also goes on and on. The current 935K3 build is almost an exact copy of the original K3 and body panels are "pulled" from the same moulds as the 1979 Le Mans winning car. Something very special! Met with one of the Kremer Brothers a few times and got a lot of support from the "old" Kremer guys on this build. So far money well spent!
For the engines;
1) Engine re-build from the original 930, bore x stroke 98mm x 70.4mm with Porsche 993 Motorsport Cylinders and Pistons, 993 turbo heads. Nothing too fancy. And BorgWarner EFR Turbos. Estimated power approx. 600BHP, 400 all day.
2) Engine to be build, all major spare parts available, bore x stroke 98mm x 66mm, flame ringed cylinders, 935 heads, GT3 titanium con rods, 935 rockers - aftermarket CNC machined, KKK K27 turbos - modified with roller bearings. Brutal, same as those old cars. Estimated power approx. 800BHP, 600 all day.
3) Engine, do have an engine case, still thinking what to do!
Ignition, at least one or two with original distributor set up, twin spark, thus 12 plugs - 2 coils - Bosch 8pin CD Boxes, aftermarket with modern electronics. One engine with twin spark coil on plug, thus also 12 plugs.
Injection, engine 1 & 2 - single injectors, brand Injector Dynamics. Engine 3 probably dual stage injectors. Need to build a "horseshoe" intake out of Aluminium sheet. Engine 1 & 2 do have casted magnesium horseshoe intakes.
In short, plenty of options to accommodate for in the main harness. Engine harness will be obviously different for each engine to accommodate for the setup.