Bought my Dec.’19 manufactured 2019 in March of 20 during the onset of Covid with the 5.3 6-speed. It has the max trailering package which gave me 3.73 rear gears in the bigger rear end housing, the rear locking differential, slightly lower stance and stiffer spring rates.
I’ve been very pleased with the power, overall mpg - about 18.5 - and the torque. The rear gearing helps quite a bit.
And I have used regular fuel during all of its just over 20k miles.
Great, great truck. The max trailering with the lower gears just works.