Yet another problem...
 

Another problem came up...vacuum is normal, according to the boost gauge boost builds up gradually without any spikes or creeps and does not go over 10-11 psi. Here's the problem: approaching redline at wot with boost ~10psi it feels like all of a sudden a king-kong grabs the back of the car and I'm trying to pull him.

Engine sound goes something like this:
uuummmmm...2nd turbo comes online...mmmmmm...braaapppp (almost at red line around 7000 rpm)

I backed off the throttle and everything went back to normal as soon as the rpms dropped a little, I haven't tried it again.

I think it's the fuel cut but I may be wrong and it it is why does it come on so early? Anyone knows what is going on?

Any one care to speculate?

TPS seems fine, within spec...
Narrow: Wide:
Open: 4.96 Open: 4.55
Closed: 1.00 Closed: 0.42

Almost full tank of gas, Walbro fuel pump

Fuel filter ??? but then why is everything ok up until 6500rpm? This, I assume fuel cut, only happens between 6500 and 7000rpm

ECU ???

I don't know if all of this is related but the exhaust manifold is still glowing red (but only visible when dark) after 15-20 min of idle and the oil level is dropping at what seems to me as a high rate. 200km oil dropped about 5mm. No visible leaking (no oil spots on the ground) so far and no smoke from the exhaust.