Darrin.
I've seen those pipes too, and I was actually going to fabriacte on for myself when I had a VN Commodore (I'm still a Holden man deep down)
The only problem being that we need extra bits welded to the pipes for the BOV and PCV.
Also, when I buy from my suppliers, I get much much much much better prices than the general public can buy at from places like GCG.