New(er) Dodge aka Ram trucks.

My brother has a 2015 3500 high output 4x4 6spd. Being in Cali can’t do the def delete, but can add the Banks monster intake and the peddle monster. The mileage is about 16 when doing the speed limit, and 18 when cruising at 80. Towing can be as low as 13 depending on the load. Shifting is slow like the NV5600 in the 3rd gen 3500 dully he has. We always start off in 2nd in both trucks when not towing. A friend rented a 2022 ram 3500 dully regular output with an 8spd auto from enterprise to tow a 18k boat, I drove it from San Diego to Portland, it drove just fine with the auto holding 55 over the grapevine and other passes along 5. The mileage down towing the trailer was about 14 but coming back the mileage really sucked at about 6 miles per gallon.