Which is really hard with all that. It just neeeds, BEGS, to have the throttle buried. The sound is just too awesome not to.

Do you NEED all that in your truck? No, but it is NICE to have. Having said that, be aware of the EPA rules for your area, and how would a different exhaust system affect your truck. You can go to a respected exhaust/muffler shop and ask questions.
Just bear in mind, you'll need to take it to an exhaust/muffler shop for most of it anyway, unless you have the pipe benders, and the right welding gear, to make your own system. Most don't. Like 87-4runner said, to get any real benefit, you'll need a whole new system. The new cat, new muffler, the new hangers, the whole nine. It can get a little expensive to have it done right. Worth it? That's up to YOU.

Good luck! Glad the fan clutch fixed your troubles
Pat☺