Cable Guy,
The vacuum kit option is probably what Inglese is asking you to decide on. It's a network of plumbing (i.e. small I.D. hard lines and fittings installed either above or below the manifold) that takes a vacuum signal from each of the intake ports below the throttle plates. Independent Runner manifolds have no other way to supply a strong enough vacuum signal. If you plan on running a power brake system or other accessory requiring engine vacuum you'll need this option.
Mike
