If you want to set up for towing, I would recomend the following in the order listed. EGT, Boost, Engine Oil Temp gages 1st. ATS split Manifold 2nd. Exhaust brake with 4 inch exhaust to the back 3rd. Next would be motor home injectors, I have 275's on mine, I am not sure what the 3rd gen would be. Edge makes a nice chip for our trucks, give them a call. You will probably want a MAG-HI Tech Diff Cover for added lube on the rear end and maybe the FastCool transmission cooler for the 6speed. You also will want to look into a FASS style unit for keeping fuel that is water and air free to the motor.
I have been to 23,000 lbs with no problems. Going down the road is not a problem, it is the stopping that you need to work on. For this I use a Jordan Brake controller. You can loose you truck brakes, but still have your trailer brakes

and good control with the exhaust brake. Hold your towing speed to 65 and you should get fair mileage. With 23,000 lbs at 65 mph, I average 15. 5 mpg. My next big upgrade will be a Gear-Vendors over drive to allow me 11 forward gears with a double overdrive.

That would my my suggestion. Hope your pockets are full, cause your wife will want to know why you are upgrading a perfectly good truck

Good luck

For lube, ditch the dyno oil and move to synethic all the way. Towing uphill on a long grade will see your engine oil in the 245 deg range. I put Amsoil in mine at 1,500 turns and have not looked back. I have 145,000 miles on my truck, still have my factory original breaks with 40% of the pads left. The Centra-Matics keep the tires nice an even for wear and excellent mileage life.
