I get a similar dip in boost pressure and air qty around 3k rpm, quite quickly recovers and gives a bit of a surging feeling from the engine...
TBH feels like a spike of boost rather than a dip, I'd assumed it was the VNT slamming full open and de-restricting exhaust...
Interesting. In the original post loss of power is described as being below 2000 rpm. Maybe the dip at 3000 is a red herring! We should be looking in the lower revs section. However, I would still recommend eliminating the egr with a blanking plate first and re-measuring.
If your problems persist, after a blank is installed, investigate the vacuum hoses first. Change all 3 including the one closest to the windscreen which is a little bit more fiddly. The one that failed on mine was nearest the bonnet catch. It looked fine but on close inspection had the tinniest of splits which had a big impact at low revs.
Confirm the rod into the turbo vane actuator thing is actually moving. Firstly by observing when the engine is turned on/off and secondly by sucking on the pipe that attaches to it. It should move about 10mm.
The next least cost investigation, if the problem is still not fixed, is to investigate your sensors. I plotted your data on excel (had to upload as pdf) and at low revs the data appears pretty random. I'm not sure really how much variation there should be here or what was happening with the car while the plots where made but there seems to be alot of inconsistency. If you car is sitting on the drive when the plots are made you should be able to reproduce the same values again and again. If it's bouncing then maybe the sensors are giving bad data. You can check the map to some extent by removing it from the inlet manifold and letting it read atmospheric. This should be 101Kpa. The maf is more complicated but not as fragile as it is sometimes described and is often replaced in error or desperation.
I've been meaning to get some plots from my car while it is working. They'd be helpful in this situation. Might get round to this this weekend and post them.
Is your car smokey?