I don't have a 2015+ 3.0, but my 2013 3.0 fix has been horrible.
Decreased fuel economy, rough idle, poor shift quality, very high AdBlue usage, decreased power (especially torque), loud engine operation.
On top of that, I don't think it's a reliable fix because my vehicles have already needed service for emission control systems.
Anyone try bringing their vehicle to a Dyno, to see what the actual power reduction is? It's said that a difference in power can be felt with a 10% change. Well, it's much more than 10% because my Porsche cayenne felt fast, and now it feels sluggish and slow. I'm sure it's much more than what VW/Audi/Porsche claim.