A friend of mine has a 98 Silverado with a 4" ProComp lift. One of the front and one rear Procomp shocks broke. So now he needs 4 new ones. Would the parts store be able to get him the right length shocks from the computer or will he need to know how long of a shock he has? Anyone know how long of a shock he needs? He hasnt called yet so I was browsing and figured Id ask (no Im not calling for him). Thanks, Mark