My 1997 T4R was an I4, 150 horse.
I moved several times with it, while pulling a 6x8 Uhal trailer. I think I may have used the next trailer down in size once before I got too much stuff! I had a tow bar and the electronics installed by a professional installer. I never had any trouble, except for the one time when the trailer was empty and I was taking it back to the Uhaul place. The trailer popped off the ball and luckily, the body of the trailer slammed into the back of the runner, and not the hitch!! The engine did just fine, don't remember any major loss in gas mileage, and I'm pretty sure I made sure to have the transmission in the proper gear. However, both times were less than 200 miles one way.
Just did the reccomended speed, and I don't think I had both the runner and the trailer overloaded in weight with my stuff.
This last move, I have too much stuff, I got the big Ford Uhaul truck, and a car trailer for the runner. Was a little weird to be driving along and see my runner following me!! Was even weirder when along Hwy 50 in Utah, the runner started honking. (Have I been in this truck with no radio for too long?) Turns out the silly cat was leaning on the steering wheel, thus honking at me!!