Send me a log and let me look at it. You need the AVCS working. The cams will slip around at high rpms and just lower overall power. Its really important to for the system to be working on this motor.
I dont know why you are saying that the VF37 is a slow spooler. I have done a couple hundred of them now. The last one I did was full on around 3500 rpm and was around the 315whp mark on pumpg as. It held power pretty good out to 7800 rpm. There maybe other things going on with your car.
C