As I'm getting ready for some HP improvements and started to look at the air intake I looked at the stock air intake. It seems that the box in from of the engine is a complicated design compared to the CAI's or replacements tubes (i.e. Yella). What is inside? Why is it there vs. just the tube going in?

BTW. I'm assuming the connection in the back is a vacuum line? What do I do with it when converting to CAI or Yella?

There are baffles inside the box to quiet the induction noise and replacing it with a straight tube won't do anything. The rest of the stock airbox and the design of the filter (flat) is too restrictive.

So, there is no emission function or so built in? My previous GTP had the air hose go directly.

What is the line in the back? Is this a temperature sensor or a vacuum line?

I will have slightly used (as in brand new with only 1500 miles on it) Yella Tube and K&N air fitler up for sale here in the neexweek or so.

I am buying a Roto Fab intake setup today and once it gets here and on the car the other stuff will be up for sale

So, there is no emission function or so built in? My previous GTP had the air hose go directly.

What is the line in the back? Is this a temperature sensor or a vacuum line?

The line going in the back of the one inlet is a PCV vent--for whatever change you'd make there, or with whatever aftermarket intake you'd install, that would just be replaced with a short tube and a new stub doing the same thing. Otherwise, no sensors, no special anything. Just the stock air filter box, the MAF sensor, tubing with the extra box baffle, and then to the TB.