vk56de, not in titan exhaust

I have been reading many of the exhaust threads on here with all coming to the same conclusion. Single outlet and 2.5 inch max.

I am swapping a 2011 vk56de into my g35 and I picked up a cheap 2.25 dual exhaust on ebay. I believe it is an hks knock off, with dual res and res off each muffler.

I was planning to have a x-pipe welded in, due to threads I read.



I guess I am beating a dead drum,, but I am trying something new.
When adding the x-pipe, how far from header flanges should I go with it?. I am on JBA vk headers with extended tubing to reach stop g35/350 location.

If from what you guys have found makes this pointless, at what point should I "Y" pipe, or use the stock g35/350z y-pipe and just single out?

Thanks ahead of time?