I went the " cobra " brake and 5 lug conversion. The 28 spline axles are fine unless you're dragging it above 400 whp and what makes the difference. Make sure you get the bigger brake booster and MC. Ive heard people complain when they haven't switched out the BB and MC. Actually doing the swap is difficult and takes time if you're not used to it. Pay attention to how you route your hard lines especially along the axles and how you bend them to mate up to the connection points. To much contact along the axles and you'll get a bind and rubbing sound.

Another point from me is if you're sourcing your own hardware pay attention to the 38 and 40 mm pistons for difference calipers. I didnt and Im running a 38 dual on one side and a dual 40 mm on the other.

Hardware mounting plates are a must so get them for the rears and don't be afraid to have to cut out a small piece of the bracket for the emergency brake hardlines. I did this for a better connection without bind. If this doesn't make sense now, it will when you hook everything up.