Don't think about the 'bahns....if those are your two choices then kicker is the only way to go. The comp vrs are acutally very nice entry level drivers, nothing spectacular but they're nice.
As far as the box goes...are you serious about buying a ported box from a flea market? Please just say no.
It is not hard to build a box, which you will then design for the subs (very important) and you will be able to pick the tuning that fits your sound needs. Buy the subs and then talk to some people on here and figure out a box design...I'll help you out if you need it, just PM me sometime.