Yeah, I built it up piece by piece.
The place you start is with a company that builds a FI controller. I used a Microsquirt by two guys named Bowling and Grippo. It's a really good product with lots of support and documentation. Also, their website has all the information you need to work up an FI system for any type of vehicle.
My FI system has parts from all over the map:
Microsquirt Fuel Injection controller,
European EX-250 fuel injection throttlebody and injectors,
Suzuki LT-R450 Quadracer fuel pump and pressure regulator,
Honda fuel filter,
Nissan automatic choke valve,
General Motors water temp and air temp sensors,
Motorola manifold absolute pressure sensor,
Innovate wide band O2 controller,
Bosch O2 sensor,
Area P 2-into-1 exhaust,
K&N 0990 air filter.
and I'm sure there are other small items I've forgotten, but those are the big items.