Im running an 034Motorsports computer in my car. It supports Fuel and Ignition for anything from a 4 Cylinder to a 16 cylinder engine. It's not cheap, but it comes all put together and it's easy to use.
That engine cover you are looking for. Forget it, at least for now.
One thing we have ALL noticed, is the number of unfinished kits for sale that people have slobbered through, they have everything (Radio, wheels, badges and even the "Lamborghini valve stem caps") except a working car. Don't be that guy. Get your car running and driving first, then worry about the fluff. And if you are going to do a V12 project, use a custom chassis and not some chopped-up Fiero mess.