Dakota,

sorry, messed up on the last post and sent to quick.  I was goning to say that I used this exact one on the LQ I did and love it.  I opted for the one without the black tank under it and just built a frame to support the whole insert and piped both the toilet and the shower drain to one tank under the traier inbetween the support beams.  It works like a charm and you only need the one grey/black H2O tank.  the trick is to raise the shower up just enough so the shower drain could flow (downhill) back to the toilet drain, that way the solids can fall straight into the tank.  When I get a chance, I will try and post some pictures.