I don't really know the answer to your question, but what I'd do is ask the TJ owner over for a couple of beers and try his tonneau cover out. Since you already run a supertop, you should already have the rails. If it fits, go buy yourself one. If it don't, then just rhino line the rear of the tub, make sure your seals on your boxes are water tight, and pull out the drain plugs <img src="/forums/images/graemlins/smile.gif" alt="" />