You don't necessarily need them, but they'd be nice to have to prolong the shocks life and have a much nice ride quality. Drop shocks fit like factory but have a shorter shaft on them so they aren't compressed so much on a lowered vehicle. A factory replacement shock is going to be the 2 1/2 to 4 inches longer than what you need, so the shocks are compressed like you've placed something really heavy in the bed.