I have built my own 4 link set up. It has some advantages and disadvantages of kit units.
I am running a watts link which is far better than a pan hard rod and using the mount on the rear of the falcon diff that i have had shortened.
The bottom link runs from the original front spring mounting point back to below the diff housing and i have used EL falcon top links which are an s shape so that I can mount the coil over on the inside of the chassis allowing more room in the wheel arch. The geometry may still require some tweaking but seems to work ok. The other advantage is that I still have the factory rear seat.
I have used coils with 10inch springs and they only have 100mm of travel so they are quite short (approx 350-380mm eye to eye fully open for memory) Running coilovers makes it far easier than to have shock mounts and leaf springs or coils mounted some other way.
Have a look in the project section under BLWNRS for pictures of what i have done. Like I said, there are some improvements to be made in the future now that I have more knowledge.