Bigger nacelles, smaller secondary hull, less fragile thicker neck and pylons with Excelsior like connection to nacelle, here's what I mean
  000000
  000000    -------- WARP NACELLE
  000000
    0000
       II       -------- CONNECTION TO NACELLE
       II 
         \\     -------- NACELLE PYLON
           \\
             \\
               ====(  ---------- CONNECTION TO SEC HULL
more or less it should look like this IMHO 
