If you pulled 4 plug wires off the 5.3L, it would tow about the same as your 5.9 does, it has that much more power. A friend has a 98 1500 with a 5.9L, and he got his father in laws 04 1500 with a 5.3L when he passed and couldn't believe how much stronger it is than his DOdGe. The 4L60E trans is pretty good for the most part, but some have had failed around 125-150K miles, but then again I have seen a lot more with over 250K miles still going untouched. It will probably need a pitman and idler arm for the front end around 150K miles, and the engine may need a set of intake gaskets(seems to be more of a northern problem). The 5.7L engine that GM had in the 90's would flat out leave a 5.9L DOdGe, and the 5.3L will make the 5.7L look like it's only running on 6 cylinders.