When we ran slash 4x4s we ran 30k-120k-20k in the diffs. The slashes don't have as many moving parts in the diffs so that is why they run so much thicker fluids than any of the other trucks.
As far as the electronics go man, that is up to you. I will never recommend anything other than an RX8 for a corr truck, too many bad experiences with everything else. Start with those diff fluids that'll get you going.