[Walt Fricke]

I don't think individual throttle bodies plus basically the same manifolds you'd use with carbs are all that expensive. Most of them use carb-like manifolds, so only the center cylinders have the butterfly directly above the port, but that isn't necessarily very bad - Porsche kept that configuration on the mechanical injection motors though I didn't understand why, since unlike the carburetors they weren't borrowing the design and parts for some other car.

As a guess, I'd think they'd cost maybe roughly the same as carbs and manifolds? Of course you'd need to pay for the electronic fuel injection, and while you were at it you'd want to include a crank fire type spark system and ditch the distributor. Now you can tune your spark and fuel maps yourself.