Hey guys just got a SJ413 WHOO HOO!

Its a flat deck I gess long wheel base, 29 or 30 inch tractor grips

and its got a Nissan diesel 1600 motor in it.
I know these arnt standerd and was wondering if anyone had any info on it?
Shes a bit rusty in places (wheel gards , roof gutter, chassis that the deck sits on

)
Im going to strip it down clean up the rust give it a bit of paint and shell be all good.
im going to trim the wheel gards, and trim the tray to better the depart angle.
So now for the important Questions

Spring over Yay or Nay? i want to but what compartments are needed?(High steer,Ect)
If i do SOA with standed SJ Axles Tippy?
Or will i need HiLux Axles? how hard is this?
Body lifts? easy?
If i was going to put longer springs in it to get improved artlication and lift what should i use? And i have some Landcruiser and Toyota surf shockies can i put these in?
How much diff clearance does a SJ have on 31 inch tires in comparasion to hilux and landcruiser?
I need traction

And without the cost so the plan is to weld one of the diffs together so it is permantly locked should i do the back will it affect steering or the front so i can use the manual hubs to switch them in and out? but steering will be affected when in 4WD.
Thanks.