I think it's the emissions more than anything else.
It blows my mind that you have to burn more fuel to reduce emissions
Someone should be factoring in the cost and emissions created to extract that much additional fuel to burn to make it "cleaner". Sounds like BS to me.
My 2000 KW was tuned way way up when I first got it in 2003. We didn't even realize how much until we made the mistake of taking it to the dealer one day. It came back tuned back to "stock". It felt like a slug, and the fuel mileage dropped from 6.5 to barely 5. That's like a 30% drop, for it to run worse. I was pissed to no end.
It lost between 25 to 30 miles per hour on hills, and burned more fuel doing it, and ran hotter.
Ok, rant over, sorry to hijack your thread.