2004 305/555 purchased in October of 2003 with 28,000 miles on the clock as of today.
1. Upper and lower ball joints replaced.
2. Drivers door speaker replaced to fix annoying buzz, still buzzs though.
3. #6 injector replaced to fix injector knock. However, 9,000 miles later the truck is knocking hard again.
4. Entire steering column replaced to fix random clicking/ticking noise.
5. Rear sliding window replaced to fix water leak that would soak the carpet.
6. Had to replace a couple of cab lights that were cracked.
I think you will find that ball joints, u-joints, injectors, and door seals are the most likely problems encountered by 3rd gen owners.