Mercedes ML350 towing hitch with travel trailer

here is a link to several weight dist. hitches for the m series

at 3000 lbs dry(4000 ready for camping approx), thats what i would do

you wont need a lot of bar tension for 500 lbs of tongue weight but that little weight transfer will make trailer control much better and even more with the addition of a sway controller as well

the issue is the soft suspension in any suv, transferring some tongue weight to the front wheels via a wd system will help immensely.