We have an '04 X with a V10 but it's 4WD. We have the 3.73 rear end and pulled a 33' trailer that scaled at about 8500 lb. We have about 175,000 miles and about half that was towing.
We did nothing to the X except tighten the steering box when we got it and it always did a fine job. It is only two of us so only two bikes and two chairs in the X and the worst number at the scales was 160 lb under on the rear axle, no numbers were ever over. Yes, sometimes in the Rockies the teach would be over 5000 for several minutes at a time but we could always go the speed limit if we wanted.