I have done a lot of research on the system and it seems that a twin rear turbo for most v6 cars will not work with a rear turbo system. Seems that your car needs a lot of displacement to make twin turbos work/worth wild. I had been trying to confirm my suspicion by looking at the 350 setup but the link was broken on the website. Luckily for me I finally got it to work by adding a '_' to the end of the link. Once there my suspicions were confirmed. The 350 kit is only a single turbo. I'm pretty sure the 370 would need to be as well.
http://www.ststurbo.com/nissan_350z_