I'm currently building a Cold Air Intake for my Car. I'm using PVC @ this time until I get all my bends right, then next payday I'll head down to the Muffler Shop & have them match 1 in 3" Mandrel bent Exhaust Pipe & then I'll paint it to match the other Red stuff I'm painting.
I do have a Question though..theres a box hanging off of the bottom of the intake tube near the TB,looks like it does nothing,no wires,just a small hose running up into the elbow of the intake. Does anyone know what its for???

 

That is a silencer/protection box. In other words, it keep your motor more quiet and keeps water from going into your motor. If you look at it, there is a large drop just under the intake hole, that is so that free water drops will fall harmlessly to the bottom of the trap and not get sucked into your motor.

You can ditch it just be sure that you do not make an easy path for water to get into your motor.

Just my thoughts.