Looking at a GMC with a 3.0 Duramax. I have a F-150 that tows like a beast and get 12-12.5 MPG towing at 67-70 MPH and 20 MPG on highway at 70 MPH. I tow a Phoenix 21 PHX and wondering if anyone would share what they’re getting on the Duramax and is it worth it going to a diesel?