Nice 15s you got there, & in great shape for 20 yr old subs too! What u have here are part of local history my friend. They are Avalanche subwoofers made here in Dallas, Tx. Avalanche U.S.A. was a local car audio products manufacturer between the early 90s, when they started out making some real nice subs like those, until they went bankrupt for bad management in th late 90s. Those were the 1st product they made. They were compared to the great Petras from Arlington, to the orions and I'd say, even better than the RFs from that era. So if I was you I'd keep em and show em some good TLC. Remember, u don't need 10000 watts to make these subs sound great. And if u ever blow 'em , they're low cost to get em back to their original glory days! Oh, and for box, I'd recommend a 3.0 f3 sealed box. That's what sounded best when I used to sell the crap out of these subs! Good Day!