Will taking my diesel VW to the dealership injure the mpg of my vehicle? If so, I don’t want them to touch it.
VW: Diesel Owners Should Get EPA Mileage After Fix https://www.cars.com/articles/vw-diesel-owners-should-get-epa-mileage-after-fix-1420681342830/
Performance will probably suffer.
I assume revising the software to make it full time compliant with the EPA regs will reduce performance and fuel economy.
Without doubt there will be all kinds of media reporting on this whenever the change rolls out so stay tuned.
If you live in a non-inspection state, and never need warranty work at the dealer, you may be able to skate on the update.