I'm using the model up, the Nissan Specific Dual Port: http://www.ebay.com.au/itm/Turbosmart-Dual-Port-Blow-Off-Valve-Skyline-R32-R34-/130553048394?pt=Motors_Car_Truck_Parts_Accessories&hash=item1e65916d4a
Just got it Thursday, put it in, and drove with it around the place over the weekend, about 200k on it. A lot more flutter than I was expecting, even after playing with the adjustment all weekend.
I installed it as a plumb back, and it works fine with the stock map. It idles and runs fine no matter what I do to the adjustment.
Reason I went with this one was because Turbosmart told me the Kompact was no good for about 15-16PSI+. Figured I'd give the dual port a crack.
I bought it from those ebay guys above, quick turnaround, everything was good. But when I bought it, the listing was for $US299 with free shipping.