If you don't know what this is, you probably want to read up about it. Basically this valve can be controlled by most EMS systems to regulate boost in real-time, such as boost by gear, boost by RPM or boost by speed. These features are essential for maximizing traction. You don't want to boil your tires at 25psi in first gear, so you set the controller to step up boost progressively as you accelerate.

These units cost over $100 from AEM, but I'm parting out my project since I have a kid now and I'm in college, so my loss is your gain.

$55 shipped to your door.