Im about to install it and the directions aren't very clear. I want to hook up the boost selenoid,2 step and wideband...also theres a vacuum hookup on the actual box..whats it for?

 

The vacuum hookup is for the Haltech's internal MAP sensor. You run a vacuum line from the plenum down to it and it measures boost. The boost solenoid should hook up to pin1 on the 3 pin auxiliary connector. The wideband has to be spliced into the Haltech harness (email Hal on this), and I'm not sure about the 2-step.