I was thinking more about some of the things that I could absolutely improve upon you experts would know about. (i.e. engine, suspension, etc. etc.) Things that a person who doesn't know anything about cars would not know but would greatly benefit 100% if they added/upgraded/etc. those things to the 4Runner.
Then again, maybe I could go on the page below and look for possible upgrades to every part listed:
1999 Toyota 4Runner Standard Equipment
I'm not sure if that's what I really am looking to do but...