My friend has a similar problem with his.
At stage 2 with the MAF sensor plugged in, the car will start and instantly stall.
When you unplug the MAF it will run, but really crappy.
We put it down to Stage 1 for the time being and it seems to run but only with the MAF unplugged.
Another thing we can notice is that when you get on the throttle there is a ridiculous amount of "whooosh" noise like hes boosting at 30psi but doesn't get past like 10 psi on his gauge.
He brought it to the Dealer who tightened small leaks in the Up and Down pipe and around the turbo as well as some "clamps". Needless to say after $570 of work, the problem is not fixed and were not really sure where to go.
It could be the VAC hoses but im not even sure where they are all located.