If your not 'overwhelmed' by the result of a remap, you have an under reading maf.
If you have surging boost you have a faulty N75 valve.
Sounds like you have both faults to me.
Easy as, and a decent tuner should have been able to diagnose this. He should have been logging your vagcom maf values to diagnose this dodgy MAF sensor.
Ive never heard of response chips, not to say they aren't any good but you should have done a bit of research before choosing which map to go with.
Buy cheap, buy twice springs to mind
Simple search on here would have brought up Jabba/Revo/CC/APR/P-Torque etc
All the best with it bud, dont give up. Change these 2 and it will be as it should