You can never have too much power when towing. The V6 would probably get the job done, but the V8, with more torque, will do the job much better. If it has 130 ft-lbs more, that will be a huge towing improvement.
You may get better gas mileage towing, with the V8. It won't have to work as hard as the V6. If you will rarely tow, using the vehicle as a daily driver, you may be happier with the smaller motor.
Jerry