Before a proper answer can be obtained, we need to know your tow vehicle, some may need a w/d, some may not. A tandem axle unit normally has less sway than a single axle unit. Your E21 is tandem. In addition there is a yellow sticker on your tow vehicle door amp with some important information, that too would be helpful. Finally, what does your manual say in regards to towing. Have you also a brake controller installed? BTW, there is a hitch dealer/installer near Escape in Chilliwack, name is Trademasters https://www.vehiclesolutions.ca
in case something is needed.