Just bought a pair of old Infinity Kappa 7's for a song from a co-worker. They need new subwoofers. I was wondering if anyone knew what kind of subs I can swap in for them. Infinity's website is most unhelpful. I would just throw in another infinity 12 but I'm worried about it not sounding correct because of differences in enclosure size/porting etc. I'm somewhat new at this, with just enough knowledge to get myself in real trouble. Any help would be appreciated.

Thanks guys.