What about the differences in sound quality.
I heard bass tubes boost a particular frequency making it more suitable for spl not sq.
Also note sumoku have an internal amp ( active subs ) but i would not recommend them at all for various reasons
Just to cut the long story short, i've heard that Subs (box) gives a thump effect (i.e dhup...dhup...dhup) . Where as the tube gives an elongated bass effect (i.e Dhummm...dhummm...)
Hope u guys understand the eg.