Need subwoofer help.

Have a pair of Joseph Audio Rm7 Sig. II speakers (bookshelf) and want the most musical small sub. possible. I would only use the sub for 2 channel music listening. With Rel now being sold I am somewhat leery and I was not impressed with Sunfire subs. Any suggestions?
Used Rel

ML depth
My REL 108 paired with Von Scweikert VR-1s, the bottom end is finally there, below 40 Hz and under $700 new. Happy hunting!
I agree that those speakers deserve a musical sub. I am a REL fan and own a Storm III, but I would suggest you check the ACI Force. I believe it's on sale now but since ACI is upgrading the looks of their subs, I would wait for the new Force XL, which should be out this month (I can't find the Force XL picture on their site, but if you email me, val at dorta dot com, I will send it to you). The Force is as musical as a REL (very similar to the famous Strata III) and almost as easy to setup, and on top of that is a real bargain in today's audio, starting at $750 each. I will put together mouth and money by buying one soon.
Easiest to set up and most musical of all I have heard.
Von Schweikert VS-1. 8 inch woofer 300 watt , dual servo(brake).
Worth a listen.
Thanks you the suggestions. I know the reputation of both of these subwoofers, definite possibilities, thanks,Richard
Check Essex Audio, used to be part of REL. Make the drivers for REL and some others.

I own the SW3 and couldn't be happier. Lots of power and very musical.
Velodyne - lots of models to choose from - great quality and sound.