Thank you for asking about this. On the Metalcloak kits we have found that is is not needed until you get to the 4.5" and up kits. With some other kits it may be needed at a lower height.
Additional bump stops should not be needed. However you should always check your clearance for all parts under the vehicle not just the tires.
I agree with cloaked, but some other manufactures will tell you that high steer is needed at 3.5" of lift or more. This will depend on the make and model of the vehicle you are lifting.