Any recommendations for a subwoofer driver?

I have a pair of ADS L1590's in my HT system. Recently I purchased an older pair of passive ADS subwoofers that esthetically match the L1590's very well. I want to use them because they look and fit my system well, but they are missing the original 10" drivers. I want to install a driver that will improve on the originals, but don't know where to start. They are a sealed enclosure and measure about 2 cubic feet internal volume.