What are the diff. in air cleaners?

[Rockstar]

I was looking at getting a chrome air cleaner but was wandering whats the difference in the 13" or the 15" or even the 8"? Do they all serve the same purpose ,is it more or less a style preference?

 

[Silent viewer]

bigger you go the more air it flows, but at some point it just gets to be too much and is over kill. i run a 14x3 cool blue filter on my car right now