Such a dumb article and "test". Simply putting the car on a dyno isn't all that's needed. The guy even claimed when you press the traction control button, it tells the ecu it's about to be tested. The jetta doesn't even have a button to disable it. The reason the first test showed higher power and no complaints about the dash lighting up, is that they probably pulled the abs fuse to disable traction control. The second run with two wheels, they had it in which then activated and cut power because the car was like WTH why are my fronts going so fast without the rears moving?! So the dash lit up and the guys were like "look, the car knows it's being tested and is going into test mode"
Freaking BS.. And at the end they said "well we saw a power cut but not really a measure of difference in emissions"
I replied on that article on jalopnik and was like thank you for showing us a standard dyno run off a stock jetta. There are thousands of runs off different cars on YouTube.