The 1500lb and 3500lb tow rating has nothing to do with the towing power of the V6 engine. It has only to do with the braking capacity of the calipers at the wheels.
What they are saying is that the calipers, pads, temp rating of the brake fluid ect... ect.. can sufficiently handle stopping a 1500lb load on your rear end.
To have 1501-3500lbs back there adds too much stress and could be dangerous and overload the capacity of the braking system, prematurely wear them out or even potentialy cause them to fail out right during an extreme braking condition.
Thats why they say get brakes on the trailer to take the burden off the brakes on your vehicle.
Flat 4 connector issue - If you want the larger 6-way or 7-way connector for like a camper or boat trailer (i.e you want a 12V power and/or Auxillary line) just simply cut it off and terminate the proper leads to the proper screw terminals on a 6 or 7-way connector. Then manually wire in a 12V power, ground or auxillary. I did this with my wifes Honda Pilot. We cut the flat 4 and wired to a 7-way connecotr we got at the RV center ($25). This would mate directly to the connector on my starcraft pop-up tent trailer. We then wired in a 12V power and ground. Fortunately I already had a 12V line wired directly back from the car battery from an aftermarket audio amp I had installed a few years back (the amp is now gone but we left the power line there). We also had the heavier duty ground. Yes, you need to make a heavy duty ground. The ground on the flat 4 usually won't cut it especially if your are towing like a camper trailer where you have more lights, running the fridge, brakes and charging the battery while driving.
