front suspension help

i have an 02 cavi.....

need some help trying to find out whats wrong with my front suspension.
my left front side sits about a half-inch lower then my right front side and when i turn the wheel its a hard knock. i was told it could be a handful of things, but also told if i just get new springs it would fix it. but i think its more then that. i also wanted to lower it about an inch. give me sum input~!! thanks

it could be a handful of things.i'd try to find the ''hard knock'' more info is needed to help!!