i was looking at these aem pulley kits, and aem cam gears. how much horsepower do these things actually add?

 

Not even 1.

 

pullys will free up a lot of power......mostly just let your car accelerate faster

cam gears will adjust the valves so they open and close closer to the pistons which will make the car a little more responsive.....but i would only do cam gears if you have access to a dyno..