I could send you a CDT Audio HD-6MDVC dual 4 Ohm subwoofer. It's the size of a regular mid-woofer with 2.75" for mounting depth. I've used these as midbass drivers in my doors. They should do better in an enclosure and they're available as singles.
They will work fine... Not very loud at all but well enough for a 6.5Has anyone used the American bass or tang band sealed? Looking for specs