Sway bars are independent of any suspension specs.
They only start doing anything when the body starts lifting on the inside and compressing on the outside when cornering.
When straight line driving they do zip!
I would advise using both front and rear from my experience.
The reduction in body roll when cornering is amazing
Thanks mate I have the same personal view, I only bought the front for time being. I haven't driven my skyline with the new sway bars I just know that when it was as stiff as this will be. (see hurts your wrist to push down on guard) It had NO body roll what so ever, I only bought a bar for it because it was new and $50 off a forum member. I've only ever used sway bars when I've run light springs like 300lbs/inch and 250lbs/inch.