Just about to add a system to a 1982 Cadillac ElDorado and want a hard hitting 18. Not sure to go with the RE XXX or MT or a MMATS Juggernaut?

from my experience the juggernaut is a seriously loud sub,

I have heard all the XXX models except the 18, but it is probably the best daily sub out of the bunch you mentioned

RE also offers then SX in an 18

Ascendant Audio Atlas 18 looks pretty nice. Prob whoop those subs in sq

Not many poeple would use an 18 for sound quality, JMO!

My church uses 4 18's for their bass

Nothing wrong with using an 18 for SQ, if you've got the space for a proper box