More horror stoies are coming out of Superchargerrebuilds.com lately. I got screwed by him too.
How big is your DV lines? and how far away from the charger is the MAF? Does it do it just cruise or when your on the throttle too?
The charger is pushing air and witht the throttle closed it has no where to go so it has to go through the DV but if it dumps to close to the MAF it screws up the reading and the ECU freaks out.
I had and Issue running an aftermarket DV cause it wouldnt open at cruise/low boost and it would cause back pressure on the impeller. Hear alot of mustang guys having issues of the impeller nut backing off cause of this too.