I would agree, it doesn't make much difference having it a couple of weeks earlier. So best to save yourself some money and be patient, just as long as you get it. $575 is a fair and average price for shipping CBEs from the US.
I'm pretty sure its been made for the G37/V36 as well at the time of development and release for the 370Z. Motordyne are the only exhaust system on the market that is modular in design and can fit both Zs and Vs or Gs. The difference is the 8" extension pipes, which is how much longer the G or V is to the Z. But it is best to contact and ask them directly to be sure as always, though I agree there website is vague. Contact them or Tony through the website, g35driver (under Hydrazine) or facebook page.
The XYZ pipe does come with the system, thats why its called CBE (cat-back exhaust, from the catalytic converters back to the end of tips).
+1 You can get the products from some of the vendors there, but Motordyne (Tony) is on there under Hydrazine.