Here is what I would do IF i had a 4runner:
1. Tint front window (not ghetto, but legal) to closely match rear privacy glass (if possible)
2. BFG AT KO 32" (265/70/17) or equivalent AT tire (REVOs, Michelin A/T-2, or Goodyear SilentArmor)...do not go any bigger because of rubbing unless you lift it above 2". At 32" size, there is only minimal speedometer differences. For winter tires, i would recommend BFG AT KO or Goodyear SilentArmor while still having aggressive look. Some people do not like REVOs in snow.
3. Junk the running boards...see #4
4. Rock sliders from ARB or Hanna or Shrockworks...IMHO, the ARB slider/step is the classiest option; however, i hear that ARB is not offering it for the 4runner.

So, check first with ARBUSA.com. See this thread:
http://www.toyota-4runner.org/showthread.php?s=&threadid=30885
These mods should make your 4runner look really cool! There are two additonal steps that you may want to consider to make your 4runner into a monster:
1. 1" front lift to even out the 4runner's stance...the 1" should not cause any issue. This small front lift should get rid of the nosedive/butt lift on the 4runner. In addition, you will get slightly more frontal clearance for off-roading.
2. ARB rear locker with on-board air compressor...this mod will make your 4runner into an off-roading monster! A locker can make you go places where you could not before with confidence. The air compressor will allow you to air up your tires with ease quickly. In addition, i think that it can power air tools too.
If you do all of the mods above, then your 4runner will easily keep up (and beat) > 95% of SUVs/trucks out there.