I think you might have missed his point.
RE: "...if everything is working in stock form, you do not need to upgrade or change anything".
That said, my OEM radiator finally shit the bed after 19 years in the South Florida heat — the plastic housing cracked by the filler cap; I wasn't going to drop in a new radiator and leave the 19-year-old stock fan (rated at 1,250 to 1,400 +- CFM), hence the desire for preventive maintenance (as well as a major upgrade to 2,500-2,599 CFM).
. . .
FWIW — something to additionally think about (yes, I'm a bit of a tech/climate nerd): the 1997-2006 model was originally designed and developed in the early-mid '90s, with the design finalized in 1993, and production beginning in 1996.
From NOAA records:
— the annual mean temperature for the United States in 1993 was approximately 50.3 °F
— in May 2025, the CONUS (contiguous United States) average temperature was 61.7 °F, or ~1.5 °F above 20th‑century norms
— in June 2025, it rose to 71.2 °F, about 2.8 °F above the long‑term average
— the most recent analysis indicates 2025 is on track to be one of the top‑three warmest years on record for global temperature trends
Point: Our climate is not the same as when the TJ design was finalized — parts designed 32+ years ago weren't designed for 2025 environmental tolerances.