Sub options with purely music in mind.

I am currently using a single JL F112. I have until June to get full purchase price (3,150) on a trade up to a Velodyne DD+18. Listed at $5,800. So I'm looking at around $2,700 to upgrade, or can pick up another used JL F112 for around $1,500-1,700. I have read many benefits of the use of two subs. Wondering if anyone has any experience with the DD+ series, or going from one, to two subs in the same room. Thanks

ejr1953, Thank you. I was kinda leaning toward the dual sub option, but my dealer insists I would be happier with the one 18. Of course he doesn't make anything if I pick up a second hand partner to my F112. I have the V1 model, have you had any chance to compare the difference between that, and the new version? Thanks.