On the subject of surge, i also had this
problem on my 1.8 using the smaller 0.63 AR hotside. There was a cure, limit the boost as it builds, or fit a larger hotside. I am using 034 EFi ECU setup but with N75, and i had to limit boost to 1 bar and let it build up slowly until 4.5-5k or it would surge like crazy, not good for the bearings! I hated it, so got Owens to mod the turbo and fit larger hotside, now i get a small bit of extra lag, but its worth it.
ME7 CAN be tuned to run whatever turbo setup you have. Maxxing out the MAF isnt a
problem either, as you can map the car with the right fuelling etc, i dont know why people worry about that so much. I know its not ME7, but my old S2 with GT35/40 maxxed the MAF at 4k! After that it was just mapped properly.
Can highly recommend MRC for mapping, they have done all of my past/current cars, and have never had any problems.
The downside of non OE Ecu setups is lack of knock control. Something that i wish i had.