id do the arb later and when you put on the lift springs you should get a ps box from an ifs truck or 4runner and i would be a great idea to regear your axles probably run 529 gears since your running 35s at this point i wouldn't worry about ram assist. also if you can afford the arb now do it all at once oh dont forget to lenghten your front drive shaft also are you going to be running dual transfer cases