I know the limit is 5000 lbs. and I've towed small boats and small trailers with combined weight of trailer and load of up to 2500 lbs without any trouble, but with decreased fuel economy.

My question is has anyone towed a trailer with a combined weight of trailer and load of at least 4500 lbs ? I want to tow a trailer loaded with a car and I'm wondering how stable the ML feels at highway speeds doing this. Has anyone had any experience with this?