IRS question

Hey Max I have a question for you. It seems redundant to me so I figured I would ask you. How come on a Jag IRS or Heidts and the like they use a forward facing strut rod off of the lower arm or uprights? It seems redundant to me because the arm has a triangulated design to begin with ( 2 seperate Bushings on the mounts) is this to compensate for not having an upper control arm for some reason or whats the deal with it?

Well I found some informaton on the Jag setup I guess the lower arm busings are to close together to support the accelleration and braking forces.http://en.wikipedia.org/wiki/Jaguar_independent_rear_suspension#Radius_Arms

I'm sure that what happened is that they designed the system and then realized that they were getting a lot of flex durring acceleration and braking, so for a quick fix they added the extra strut bar. You'd be surprised how much flex is present in a factory suspension.