The SP (anti surge cover) was implemented on the BT twin scroll kit mid February of 2013 on my own car, a 350Z:
http://my350z.com/forum/forced-induc...from-bp-9.html
Just sayn'n.
As for the reference to the JTran kit, which is a twin scroll kit, I did not copy it.
Compare the manifold pipe routing of that kit to my:
Jtran Studios Presents turbo kits (fabrication thread) - Page 2 - MY350Z.COM Forums
The turbo location is shared, but the primary and very important design difference is the equal length primaries on the BP manifolds, which separates the two kits. They also made the passenger side primary go over top of the transmission, which again is very different from a design point of view.
As far as the whole "mid-mount" turbo stuff goes...the term wasn't even around till I started with the very first kit (which was a true mid-mount since it was right in the middle of the car) on my own 350z back in 2009
.