disclaimer: I own a 2014 TDi Passat with 6M and I have averaged 52.1 MPG over the last 37k miles. those 37k miles were done in just 1 year.

The vast majority of folks aren’t going to notice a .6 second increase in 0-60 time. The MPG drop is somewhat unpleasant, but in the grand scheme of things you’re still getting 45+ MPG. Far better than most vehicles.

Not sure if 4 mpg is a “plummet.”