Okay, I will attempt to tackle the ones I know about here since no on esle has (I'm sure someone will soon fill in the rest).
A modded air intake will get more air into the engine (more air into the gas=more cobustion=more power). The best of these is the Cold Air Intake which includes some sort of heat shield to keep engine heat out because cold air is denser than warm air and therefore even more air ends up getting in. There are other ways to accomplish this, but they're not quite as good (insulated intake or just a plain one). The tips I've picked up are, keep the bends in the new intake pipe/hose to a minimum (every bend reduces pressure), get a smooth one because any texture inside the pipe/hose will create turbulence and reduce air flow, and get a heat sheild if you can.
As far as a chip, there are companies that manufacture chips for any car you want...you specify what you want and it'* burned for you, however, wait until all (or at least most) of your other mods are done because many mods will confuse your computer (like bigger wheels/tires messing up the speedometer) and the chip can be used to change factory settings so that can be corrected. They can also remove speed limiters and such.
And a larger throttle body, again = more air
If you have time, read through the whole techinfo section (there'* not that much), but definately read this one... http://www.bonnevilleclub.com/techinfo/?article=52
and this one since you're interested in pulleys... http://www.bonnevilleclub.com/techinfo/?article=50
Hope this helps a little.