Its not the same for turbo models. You'll notice tiurbo models don't even have this box at all. The reason for this is a turbo provides forced induction. This means that the response is forced. While there may be lag before the turbo spools, the response is a lot bigger when a turbo is forcing air down the intake pipe.
Any change to your intake will change the sound of the flutter, bov and induction noise. It all comes down to preference I guess
I agree, the shiney piping looks hot, but not worth while in this case. Have a look at a stocko commodore intake pipe and then compare it to the aftermarket one your friend has. The intake setup on a commodore is totally different to an RB.
Definately get a cold air intake for your pod. It will make a big difference. Some people have even said their performance drops by having a pod open in the engine bay and went back to the stock air box. A cold air intake will fix this. Get something made from stainless. It will sheild the heat much better than a plastic sheild. And piping to the front of your kit would be good too.
You will notice indents under your air filter that look like they forgot to cut two holes. This is where the turbo models piping for their side mount intercoolers run through. You can cut a hole there to feed your air filter.