My 2003 Silverado has 36K miles on it. I towed 2 28' racing sailboats stacked on a trailer over 2000 miles last week. The boats weigh 1000 lbs each, the aluminum trailer 500-600. All up with other gear likely about 3000 lbs total. Not heavy but decent wind drag. Over $100K in the boats, so you got to be careful. Never really noticed a poor ride with the original shocks, just noticed with the trailer in some rough construction zones with lane shifts, I would have liked more control and better damping. Most cars I've ever had don't need suspension replaced that early, but have wanted some better shocks for a while. Thought about some KYB, but wanted Bilsteins. Didn't want to be penny wise and pound foolish, I installed Bilstein Heavy Dutys the other day. They are great and would have made my truck more enjoyable had I replaced the cheapy OEM shocks a long time ago. My truck doesn't have the Z71 package, which comes with some type of Bilsteins, maybe with different valving than the aftermarket shocks. I've concluded the OEM shocks were junk the day they were installed.