E-truggy or conversion

ok i have a rc8t ft and mikes full conversion kit on the way. Is there anything in particular to pay attention to when building the kit(first 1/8th) the diffs say factory built, is that built well, or do i need to take them apart and shim them? any tips or problem areas to pay special attention too would be helpful to know about ahead of time. any special tools, new oils for diffs or shocks i need to have on hand

thanks all