for a $450 total budget, you'll have a hard time getting any shocks that will withstand the abuse of a "pretty low" ride hight for an extended period of time. Used springs are a good way to save some money if you KNOW how many miles are on the springs and how they were treated. Used shocks should be out of the question unless they're rediculously cheap. Considering your goals and budget, I'd look into KYB AGX shocks.