I just sold my Spiderbox and a few things....
Get all the heavy duty BD parts. Get the buggy- depot heavy duty A-arms (even), spindles, ball joints and rear engine mount (chain tensioner).
I also recommend the reverse kit and the better steering rack. This will all set you back around $500 ish so brace yourself, lol. If I were to boil those down to the most necessary, I'd say get...
Reverse kit ($250)
Balljoints ($100)
Spindles ($100)
Give or take that's the cost... I also used some stock plastic sheets to make a makeshift hood and I also used some trampoline net to make some "windshield" netting.