Actually getting to play with this on the dyno right now. 2016 C7Z A8 upper lower pullies, H/C, Ported blower, headers, intake, meth, and nitrous.
First thing I did was smooth the areas I was seeing throttle closing and it definitely helped out there if not solved it completely, but having issues beyond 6350rpms. Logged maximum engine tq follows same curve as actual but zeros out at 6350rpm every time.... At that point dyno shows Tq and hp tanking. Wonder if this going beyond bounds?