Hey everyone, sorry to ask one of the questions thats been talked about a million times but i'm still confused. Can some one just tell me which example is right. And what the hell is 2.1"? why not 2"? Thanks, Dan

 

Top picture (Example 1).

The reason for 2.1" as opposed to just 2" probably has to do with the desired down angle of the headlights, though I don't know for sure.