Well, we bought a '97 4runner and seems to be all we can think about right now. I found a couple of web sites that talk about how to get more power out of the bad boy. One option is by suppling the engine with more air by opening up the the air intake. One method is to buy some after market parts. Another was to cut a hole in the air box which houses the air filter. Both looked interesting. The after market parts claimed to add about 7 horses to the engine and there was no guess at what the "home" version did. Although the guy said he could feel it more in the low end and seemed to have more torque.
I like both options and am thinking maybe a combination. There is one part that you bolt in between the air intake and the manifold. It claims to create a vortex of such that helps aspirate the engine. There is another after market part that replace the air intake tube that claims to open up the flow. Basically the factory one has some reducers on it that don't let as much air through. The "home made" version has you cut a 4.25 hole in the air box and install a marine screw cap so you can put it back on if you need to. This lets a ton more air available to the engine.
Well, not sure if I will do any of these but it is amazing that people think this stuff up!
~Hosh~