A three link and a torque arm are different designs. The torque arm constrains the arm to the rear end in rotation. The three link has three longitudinal links that can use sperical joints on each end. See the following link for pictures. The general layout has two lower links outboard. The single upper link can be located in the middle or on either side.
http://www.chassisunlimited.com/product/link-suspension-kits/3-link-suspension-kit-e.html We agree.
On a further note, the location of the upper 3rd link off center, has useful bearing on the end result handling characteristics, ie its location is not random.
