We have that with a low mount T67 and camtech drop ins, the std manifold was a restriction over 300 we topped out @ 327 dropping to 320 after about 10 pulls with the t67 in a conservative track tune. We gained about 15rwkw consistant through the mid and top and found it would hold more timing on top again due to the drop in exhaust pressures. Manifold was a low mount 6 boost item with matched runners, they had to do it twice but the second one was bang on and with a similarly conservative track tune pulls 340rwkw repeatedly.
The original manifold had two gate outlets (either side of splitter) going to one blitz 47mm wastegate (dual outlet gate).
http://www.skylinesa...ttach_id=142838
I dont consider this test to be a rule, just what we found... same car same mods just a different manifold.