After searching for an answer as to what this does I haven't found anything. It's attached to the ram air "thingy" (for lack of better terms), can I remove the ram air plastic setup since I have an intake or only remove this If I have the CAI?

Thanks

 

Boost sensor is what nissan call the Manifold Absolute Pressure (MAP) sensor. This, along with the MAF help the ECU figure out how much air is flowing into the engine.