How do you figure? The Audioque HDC3 is $239 from their site and the Fi Audio BL15 is just under $300. IDK how much the RE MX is though, but from the looks of it, I can definitely get a loud sub in that price range. If you think I should up my budget a little for something else, feel free to suggest something though. are the HDC3's even in stock???
I actually think the only difference will be the enclosure you put them in...if you want great low end id say go with the q's and go ported...id say if you wanted all around sq go with the ss and put them in a sealed box... just my opinion...
I'd say DD1508's...i think they're like $150 each so within your budget...they can get pretty loud and are impressive for 8.... Also ascendant audio is supposed to have some good 8's...but no face to face encounters with them yet..