Wheel lock sizes??

I have a 94 ls and I just bought custom wheels. I want to put on wheel locks becuase where i live stealing sh*t from cars is a parttime job. Anyways i have no clue what size i need. My brother told me that I need a specific size because i have custom rims. What size do i need? They are 16" enkei's. I have 75k on my car, should I get all new lugs as well? What kind/size should I get? Please help me because I am clueless....