Pretty much all short ram intakes are the same. Some vary in diameter tubing, some very in cone filter size, and some just vary in dynamics all together. Take for instance the J's Racing Intake. The design of it is to increase the velocity of the incoming air. This differs from most other brands, who use a set diameter piping. If you're looking for cheap, pretty much any intake that can withstand a good amount of heat will work for you. You'll also want a good oiled filter on the end, such as K&N.

If you're wanting to lay down a little bit of money and get something that performs a step above, go for the J's Racing.