Back to back R32 std dumps and equal length front pipes (unsure of brand but quality jap) and the greddy front dump combo kit. Car tune was untouched and both pulls were done at the same AIT, oil and water temps (within a degree or two).
Included ambient temp comparo so you can see it is indeed not a correction variance
peak and power from 5000rpm was near identical power but we saw 18kw and 56nm @ 4000rpm upto 34kw and 69nm @ 4500 on this GTR, i reckon with tighter gate adjustment it would have been even better (as would the std runs) but you can see i pulled out of the run (and tightened gate for the next round of runs).
May be worth asking 9KRPM for an independent opinion as he saw some gains from memory.
I generally dont bother getting customers to fork out the extra (the greddy items are hell dear) as the stock gear does the job nicely (especially R34) even the std manifolds are not worth changing, but if the customer want every last NM its the piece of kit i recommend. Others may get better or worse results but all i can do is post my results.