Re: King Springs for AU falcon xr6
You won't need new shocks, front or rear with those springs. All King springs for the AU Falcon sedan are designed to hold trapped with the factory shocks, even the SSL's, which are now known as UL's (Ultra Low's).
BTW, King Low's (part No.KFFL-57) for the front are almost exactly the same height as AUII/III XR6 fronts, so won't be much lower than it already is if your XR6 is a seriesII/III. Fitting SL's at the back will even out the ride height level front to back. I'd just do the rear springs.
Is your car an VCT (IRS)? What part No. do you have for the rear springs?