I had a 2004 D/Max 2500 to tow my 31ft 10,500lb 5ver. And it did a good job for the past 10 years.
I decided to trade last year and after lot's of indecision decided to buy a 14 Silverado with the tow pkg. rated at 11k lbs. This truck has a 5.3 and tows my trailer almost as easy as the 2500. Mileage is about the same with the only noticeable difference being the long hills. The torque of a diesel is hard to beat.
I drove to Florida return this year and never felt our of control or underpowered, set the cruise for 63 mph and smooth sailing.
Quite a fuel price saving with gas vs diesel.
