Suspension Help

[Royalblu68f100]

I am working on a 1977 F150 and plan to transfer the parts to my 1978 Bronco project after I have the cage and bodywork straightened out. I plan to use this truck/bronco for mud bogging, and occasional trail use. I currently have a 2 inch leveling kit on it from JBG, with 35" Super Swampers. I will be picking up a set of axles D44/9" this weekend with Detroits and 4.56 gears. I ultimately plan to run up to 38" TSL's, boggers, or Rockers, also have a 460 and 4 speed for the swap. I have read this forum for a while and have a few questions.

Who makes the best 4" suspension "kit", how good of an idea is it to do a shackle flip (instead of springs), is there a "doubler" kit available, can I install high steer arms on my 44? I have others but I feel best to start with those.