You do have to use the WR y-pipe(at least on my set I did). I was going to keep the BAT y-pipe, but it would not bolt up. It was off by about 1/4 of an inch. I don't know if this just something they did when they revised them, but the manifolds do come out at a slightly different angle.
BTW, I had to redo a few things and pull out the EGR tube. I took a picture of it and will post it in a few minutes. That should give you guys an idea of what needs to be done to make the EGR work.
