Put the blowers back on...

X2 I'm sure that would be the cheapest and easiest way to make it go again .

pull the map sensors odd and see if they installed a restrictor in the vacume port to keep booost out of the map sensor..

If anything at all was done to the MAP sensor, I would think it would be that a two bar MAP sensor was installed, which is able to recognize boost as well as vacuum. Even so, I'm not positive that would cause an issue while running N/A. You can get the GM part number off your sensor, and check it here:

http://www.robietherobot.com/storm/mapsensor.htm

what did you do with the fuel system ? thats a major change they do for the procharger install....

Put Blowers back on...install O2 bungs in exhaust to get AFR right...hire a good tuner...pay him $1500 and call it done.