I have an 06, manual. Most of the original system is still in tacked. Mufflers got chopped off a few months ago because unlike many fellow gents here, I enjoy the loud noises coming from the 4GR 😄 I also don't have secondary cats, but not an issue for MOT, still passes with flying colours.
Original systems tend to rust around the joints where one section of system meets another. Before I got the mufflers delete there had been several repairs done to the joints between the middle section & rear sections.
Maintaining longevity can be obtained by using 99 fuel, dipetane fuel system cleaner and allowing the engine to warm up for 10 minutes. 👍