I got a hub to hub D44 I am rebuilding. I went to Autozone and got rotors for 30 dollars each. However, not thinking they did not include hubs (this is my first axle project) So I go back down and inner hubs are 70 dollars. Or I can get rotors w/ hubs for 170 each. So what is the difference? How come I can get the rotor/hub seperate for 100 each compared to the 170 for them together? Also I bought Milemarker locking hubs so will they fit the two piece? Thanks!!