techinspector is right on with measuring all of the ride heights on an existing car. use the threaded rod to set ride height on removed sub. also, take a few minutes to hang your fenders to make sure your wheels are centered (before you weld anything). the stub can either be spliced-but do lots of planning and bracing, otherwise i've seen a very wise builder use the whole stub(locating the stub below your frame which gives you greater integrity with the longer mating surface)