Actually, it is literally plug n play. Plugs into the diagnostics port under your seat and reads directly from the ECU. There is a slight delay between shifting and the reaction of the display but it works quite well and should set you back around $150.Don't think it was "plug and play" as they say. I'm sure wires needed stripped back etc etc.
Here's what it looks like in action (red display on the right side of dash):