Okay, its one of the following me thinks,
1. MAF is knackered, this can be cleaned with brake cleaner, look up a thread about cleaning it on scoobynet. If cleaning it doesnt sort it, try a borrowed working one.
2. Type Rs are notorious for lunching thier ignition leads. I dont know why, but Colin Greer replaces every type r set he sees. Check them once again with a borrowed set to eliminate them.
3. check your plugs, they could be fecked.
I doubt the DV is causing it as you would see boost loss if it was leaking.
If these tests dont eliminate it PM me and we will go a bit further.
Callum W