Yeh, finally someone interested in Xtnat subs and not just their amps. You have to be very careful with these subs. They say 500 watts RMS but its not quiet that high. They will pound with that much power but the center peice will come unglued and start to vibrate and make noises. Also they have had a couple different probs with the tinsels, used to have tinsel slap but they fixed that with some foam, now they seem to break fairly easily with extended play, I don't know if they were to short or couldn't stand the heat or what but my new ones seem to be holding up. You have to build the boxes just right for these bad boys. Xtant has a great site for this stuff. Regal they have all the specs you could want too.
www.xtant.com