An excellent point - my first civic ( a 92 vx hatch) - had a "CAI" built from a $25 short ram pipe from autozone and a dryer vent flex pipe - ghetto as hell, but seemed to do the trick.
The only reason why I say AEM or Injen (feel free to laugh and point) is for aesthetic purposes. Just want a one piece pipe that looks pretty.
I ended up buying one off of Car-stuff.com, cost me $260 - quite pricey - but its got the cool powder coat blue and I think it comes with a reach around.
For anyone reading this post... both the above posts are correct, a pipe is a pipe, simply providing the most turbulent free cooler air supply for the the TB, there is no practical need to spend the cash on some name brand. I suppose I've gotten snotty in my years of doing this stuff.