Bumpstops do not affect ride height. Springs determine ride height.
Cutting bumpstops allows for an additional inch or so of travel near the bottom of the damper's stroke. This is a benefit for lowered cars, since they have reduced shock travel lengths compared to stock. Cutting, or even omitting, bumpstops will not change how a car sits. Bumpstops prevent shocks from being damaged from being bottomed out. Bumpstops do not change the behavior of a suspension system. They are a rubber buffer to prevent metal to metal contact within the damper.