According to the info on Mike Focke's site, you should get a reflash if you go
from the 996.606.124.00
to the 9
86.606.125.01
http://sites.google.com/site/mikefocke2/checkenginelightcausedbymassairflowsensor
If you originally had the 996.606.125.00 version, then a reflash isn't necessary.