46rh questions

An additional external cooler never hurts
And compared to the overall cost and amount of work to overhaul the trans a few upgrades don't hurt (like the heavy duty servos and accumulator) and also heavy duty front band strut, for example) also won't hurt, won't effect shift quality, as often parts like the accumulator switched to being made of plastic.
Stock servos have been known to crack though not real often.
Also there were a few years where there was something wonky about the apply piston where they would leak fluid pressure internally, I've had notices that the piston seals in certain kits (last time I used transtar) included in the kit box claiming "updated seals" to somehow compensate for it. . I'm not sure if that carries over to the 518, definitely on the a500.
I had just this on an a500 in a 99 Dakota I used to have and it caused a flare up between 2-3 shift.