Have you tried searching the forum yet? There's a ton of good info out there, you should do your homework to narrow your inquires down to something that hasn't yet been asked before you post a thread.
That said, I know (from personal experience) that it can be overwhelming at times, as it often seems like everyone has a slightly different question than you.
I'm by no means an expert, but I've just gone through a similar process with my own new-to-me 02, so I'll give it a shot.
First, why do you want to replace the shocks and springs? Is the rear sagging? Do you want to improve the ride? Or are you just looking to do some preventive maintenance? I'm assuming your springs are stock, but what shocks are you currently running? When were they installed? Do you have reason to think they'll fail soon?
Unless you're having sag issues, if you're not looking for a lift, I wouldn't bother with new springs.
If you feel like the shocks should be replaced, 5100s are a good start. They work great on non-lifted trucks and allow for up to a 2" lift if you should ever decide to change your mind. Make sure to get ones for a 3rd Gen 4Runner. There's some info out there on old threads that will direct you to a different model (back before they made 3rd Gen specific shocks).
