I doubt the diesel injection will not work. I have no experience with VW diesels but extensive experience with small/medium and large marine diesels, they regulate the throttle by regulating only the fuel. No air volume sensing is used.
I will be building a low buck EFI for my engine once it is up and running on carbs. I will be using a MegaSquirt to control it, a 944 2.5L throttle body and custom (homemade) plenum and runners. I hope to do it all for less than $400. The MegaSquirt does not control the ignition, but I have a vacume advance Mallory so that is tuneable enough for me.
For injector/fuel pump sizing try
http://members.tccoa.com/jmiller/finject.htm . For throttle position and other sensors you need to know the ECU you will use and pick compatable sensors.
For throttle bodies, pick one from an engine that makes about the same HP you are shooting for.
ken