I have a 92 Blazer with horrible steering issues and front sag causing the tires to wear really quick. I am trying to decide which parts to replace for the front suspension. The suspension has never been messed with other than shocks. How can I tell if the upper and/or lower control arms need to be replaced or just the ball joints? Would new coil springs also be a good idea? Are there any other pieces I should check? Any suggestions for the best retailer. I appreciate all advice and thanks in advance.