Cone flex on a square sub is different than that on a round. That should modify the sound slightly. Will you ever tell the difference? probably not.
does the shape of a sub make a difference to the sound? i thought a circle one would be more even sounding but yeah is there a difference?
Yep. substantial difference. Besides the fact that the square subs you're talkin about are Kicker Solobaric's, which require less airspace to operate (smaller box for bigger sound), there's also the fact that cone size (the area of the surface of the speaker) dictates to a large degree how much sound you get out of it...and a 10 (or 12 or 15") square has considerably more area than a 10 (or 12 or 15") circle.
Ya, my l7s kik lotsa ***! The square does save space, can hit, and lool awesome IMO. They should be a definite option.