haha yeah all those things can make sense, but all unlikely...it doesn't feel like it's labouring the engine in low RPM, it just feels like it quite simply doesn't have any power. Not like it has power, but is being held back...although, there is an audible ticking sound come from under the car while idling (clutch in or out doesn't make difference) but that has been apparent quite some time ago and then went away...came back recently though, so it might be related.
if the intake cam skipped teeth, that could explain lack of power while still maintaining correct boost. Boost shown on the gauge is simply an increase in manifold pressure...doesn't mean the same volume of that air is making it into the cylinders. Depending on which direction the gear skipped teeth, it could perhaps somehow limit the amount of air entering the cylinder? Open duration would obviously remain the same, but this would be to the same effect of VCT changing power curve.
I can almost guarantee that the piping from turbo outlet all the way to throttle body is free of leaks or blockages. This is with the exception of INSIDE the intercooler, as there's no way I can guarantee that hasn't somehow become blocked. This is because I redid all the piping myself with the 10mm nut T-bolt clamps, after degreasing all parts first. Only joins that weren't redone with these bolts are the 2 on either side of the very final silicone piece before the throttle body.
Also fuel pump and filter are only a few months old. Pump is a bosch 044 running in-tank. a couple of times it has been noisier than it usually is, but I haven't been down on power specifically at these times. I put it down to cavitation or something to do with getting warm.