Engine Upgrade recall CX5
 

Iv'e just had my engine management upgraded, It said in the recall letter "to improve throttle response and quieten the engine" When I asked the dealership to clarify what the upgrade does, he said "they didn't really know,but thought it was to reduce the engines emissions and pollution".
Anyone have any information on this? I have not observed any difference in engine noise or throttle response!! so far.