Torsion Bars don't like being lowered all that well. Trust me, I've been searching to do it on mine. Essentially, what my conclusion has been is that the Rear can always be lowered. There are all sorts of options.
The front is the main problem with T-Bar type trucks. I think the best solution would be probably doing a Coil or Coilover conversion, but even then after you do that you'd have to alter your Control Arms to accomadate the lowered ride height. Not sure if you could hack together bits and pieces of like a DJM 4/5 kit to do this or not. I may investigate later on, but for now, I'm happy with where my Sport sits.
1999 Ranger XLT -- "Project Unknown"
2010 Subaru Impreza -- "The Daily"