I’m in late on this, but here
I’m in late on this, but here’s my two bits worth. I bought a new 2008 Sierra 4.8L. It did not produce much torque, and yielded poor fuel economy. It barely managed to tow our 19 foot trailer. In 2019 I replaced it with a new 2018 Silverado 5.3L. What a difference in towing, and roughly 25% better fuel economy. On our first 600 mile run (bare, no trailer attached) it gave 30 MPG. Two drivers, one with a lead foot. Genuine, real life, 30MPG.
I once had a Ford salesman who listened to my needs advise me to buy the 5L V8 over the turbo 6. Less torque, but cheaper and more trouble free. Just his opinion. But it seems clear. Buy what you need. The guy who said the soccer moms might be the target market for the 4 cylinder turbos has probably got it right.
Even if you could prove the turbo 4 could pull with the V8’s, it’ll be using more gas to do it. And you can bet, will be much more expensive to own long term.