I'm pretty sure the 2015's fix was software only but 2012-2014 NMS is phase I software to be followed by a phase II hardware (and software too?) fix. There is some information on this in the Dieselgate sub-forum here. I believe the phase II hardware was approved and is starting to be released to dealers but AFAIK nobody has reported doing phase II yet which would include how it affected the driveability and fuel economy. Hopefully someone with more knowledge than I will chime in on this.Was the "fix" for this car just a flash? or was there hardware put on too?