I have a VW TDI. There is US spec software and European spec software. A friend got an illegal copy of the European software and got 10% better mileage and improved acceleration. When he took the car in for something else they changed the software. He was unable to get the old stuff again as his source (mechanic) had moved on to something else. He was very unhappy with the change.
I certainly won’t let them touch my car for anything as I’m happy with it now. Changes made to tweak environmental numbers is often just that, a numbers game; like putting an air pump on to change the ppm without actually decreasing pollution.
Political science at work in the automobile engineering field. Like global warming, the official figures are fudged to make a specific outcome show up in the stats, but the reality is often much different. By demanding conformity with a certain set of parameters, often a whole different but directly related objective is skewed off to one side.
Compare this with the effort to make the cholesterol count of every patient conform to some hypothetical standard. Taking certain drugs MAY force the cholesterol count to get into some “desirable” range, but at the cost of dislocating much else in the body metabolism, flushing out some highly necessary and vital blood components along with the “excess” cholesterol.
Sometimes the “cure” is of much more grave consequences than simply living with the disorder.
“When he took the car in for something else they changed the software.”
I’d be careful ever taking your VW to the dealer again either. One outcome, almost for certain, assuming that you’re even allowed to keep your car, is that you will have new software pushed, and you won’t like it. It’s almost worth going to a junkie to get a computer you can swap-in the car just for dealer visits.