My 4/4 would bottom out at times when it was new and I swapped out the rear shocks for adjustable ones and once I found the setting the suited me best, the bottoming out was a thing of the past.
The added benefit was being able to stiffen them up a bit more to suit my needs.
IMHO, I would do the shocks first. A bump stop kit will of course stop you bottoming out but the weak link here is the shock not doing it's bit in preventing it.
