For what it is worth...I have a '99 5.3L and it is currently running on 223K mi. My fuel pump went out at 140K and the trany was rebuilt at 160K other than that it has been a perfect truck. The seat is a quick fix at the upolstrey shop if it bothers you. Mine can be fixed for less than $200 bucks. They are solid trucks. That model has heavier sheetmetal which the body shops like for welding on when the body rusts out. Your in FL and may not have the rust issues.
Keep the tires rotated and properly inflated, cant go wrong with a set of michilens!