shOrtlife, I agree completely, There are quite a few companies that deal in those blowers and are experts at setting them up for high boost levels. However they can never equal the more modern designs. The current Roots have very good adiabatic numbers, the Eaton M62 has a maximum of 66%, certain versions of the Eaton TVS have a max of 76%. Most reworked GMC blowers are down in the 48% range.
The bigger problem is the volumetric efficiency curve. The blower is so larger that with any reasonable amount of boost on an Alfa 2.0 it will be operating in an area where the volumetric efficiency curve is very steep, this will result in relatively weak low and mid range boost.
Duk, sometimes I am a little slow. I got the sarcasm now
Greg