I am also  running the birfield elim. kit and has stuck the tire in some nasty spots at funny rocks in washington where I was holding my breath, waiting for a nasty bang to come from the front end from running 39.5 and a spool in the frontend. Instead the rear 3rd gernated then the shortside warn hud, so needless to say the only wheel was the longside and I had to put alot of power to that wheel while being pull out of the trail, then back to camp. 
But my question was for Alpha, is that a 1st gen frame with a 3rd gen cab? how much work was it to line up the body mounts? I have a 1st gen and was thinking of doing the same thing but putting a 2nd gen cab on. I measured the mounting ponits but they were different besides the front one.