You dont actually need an amp for any of the speakers. But yes, the audiobahns can take a lot more. I have a set of 3 way 6x9'* and 3.5'* and i am actually using the 6x9'* as subs. As in they are in a large box in the trunk and are amped. This is just a temporary kinda thing. I am not saying they are good though because they are known for being low quality speakers. I think i got my two for 25 plus shipping on ebay new.
I actually have a vid here of the bass-ness but my wireless conection and putfile dont mix.
Finally.. This is the vid. NOt the music i usually listen to but for a vid like this i had to use this music.