I'm from Romania, and i have an mk5 gti 2006. I have same problem as you had. "MAF unplugged = car runs better WTF??"
Can you please tell me how did you figurred out this problem?
I have also change the plugs,coil packs, pcv,dv,n75, maf sensor is new, but the problem persist. Rough idle and missfires on cyl 4 and 2 under WOT.
When i plug the maf out, the cars idle much better and there is not any missfire under wot,the car runs much smoother.
Waiting for your response.