I am thinking about getting 2 10" kicker subs. I noticed that they have the traditional circle shape and they also have a square shaped sub. What is the difference between the two? does anyone know where i can get some boxes that will hold the square subs or will i have to create my own?

square subs are called Solobaric, nice hitting subs when in the right box. go to a stereo shop im almost certain they will have a box for them in stock.

what is the diff between the solobaric ones and the circular ones?

just different design they both are subs just different shape for whatever ur into....haha try goin for an 18" solo x haha those are huge and hit hard rms is 1000 alone haha they are pretty expensive tho.....

a friend of mine said the solobaric subs hit harder since they compress more air. is this true or would the solobaric 10" sound the same as the circular 10"?

The solobaric has more surface area than the circular sub, so it does push more air.
Never heard a Kicker solobaric, but all their other subs pound very well.

what type of material are most sub cases made out of?

boxes are mostly made of wood and plastic screws sealing solution (caulk) carpet neons.......i think the solobarics hit harder...but the round ones are still good...

get the solobarics.... they are WELL WELL worth the extra money.. beleive me i know i have 2 of the circle Comp VR12'* and i put 2 of the L5 solobaric 12'* in the trunk and its a world of difference, i would highly reccommend a "ported" or "vented" enclousure for the square ones, as they dont perform as well in a "sealed" box.. if you opt to go w/ the circular ones use a sealed box.... im just throwin my .02 in and speakin from personal experiance w/ kicker products

I bought 2 solobaric L7s off of ebay for $264 dollas

For the boxes, does it matter what kind of wood I use (resonance etc) or can i just go to the nearest lumber place, buy some wood and build a box? For ported/vented boxes, would i just cut out some holes in the side of the box? what is the advantage of having a ported/vented box instead of a completely enclosed one? Thanks everyone!