So I have moved several hundred pounds of gear forward in the garage portion of my trailer (over the double axles), AND I had another Curt Manufacturing sway control installed on the other side of the trailer tongue. This has all but eradicated the sway problem I was having, and I have towed the trailer up to 70 mph without any issues whatsoever with my little 3.0i. Certainly if we had any real hills/mountains here, the 4.4 or 4.8 would be needed. Or that 3.0sd due for release this year!