I haven't done any of the above. But I have replaced the 3rd cat with an H-pipe and replaced both front air shocks with new ones from Arnott. That's about it beyond regular maintenance with 192K miles.
Oops! Edit: I forgot, I also replaced the UCA's, LCA's, sway bar links, and tie rod ends in the front end. Pretty much rebuilt the whole thing. Can't believe I forgot about that!!!!!