Hello, I have a 2007 Chevy HD2500 Classic 6.0L gasoline engine capable of towing 10,300 pounds. I have been towing a travel trailer weighing 5,000 pounds. I am trading for a heavier trailer weighing 7,300 pounds. In the past I have been able to climb steep grades out west at 65mph - I generally do not travel faster than 65mph to ensure I can manage the truck and trailer when a tire blow out occurs or other issues. I am concerned that I will not be able to maintain the 65mph on steep grades with the new trailer. I have considered modifying the exhaust and the intake, or possibly a performance chip. Any recommendations for modifications to the motor to ensure good performance on the freeway pulling a heavier trailer? I only have 31K on the truck and do not want to buy a new truck. Thank you!