Has anyone added a small subwoofer to 2 channel and been thrilled with the result?


The subwoofer can of worms.
I’d like to add some bass to my otherwise fine 2 speaker setup and have limited space so perhaps a single 10in?
After a few weeks of research the only conclusion I can come up with is - everyone agrees they have to be setup properly. Every brand and technology has their own following and most recommend using 2 (which I don’t want due to space concerns). My room is 12 x 13 ft with box raised ceiling.
After much research, these are the subwoofers I’m trying to pick from, for various reasons:
Rythmik FM8  - lots of hifi fans
JL audio e110 - fantastic support
REL T/9i - sort of a gold standard
KEF R400b - interesting technology, makes me grin. 

I've never heard any of these.
System:
Hegel H160
SF Concerto speakers on stands.
Ben
casteeb
I bought a Rythmik f12, i have been running them along with my Scientific fidelity Crown Jewels. I have also ran them with my Acoustat Monitor 3's crossover set around 60 and it was surprisingly coherent and musical.
Upgrade from a Def tech sound field 15 to JL F112 v2 and realized everything I had been missing. I could not be happier
You should seriously look at Paradigm’s new Defiance Series or their Seismic 110, depending on how much you want to spend...http://youtu.be/tJJtWokUIWk
Oh yes ! I love me a good two way. When done right nothing images as well. I also love subs. That being said I have only heard a few that are done right. A sub should Never be noticed but rather bring a presence and fullness, Kind of like a good flavored cream does not hide the coffee taste it just adds to the pleasure !

 I am currently running in my second system, a rebuilt set of Watt 3.1 heads with a smaller Velodyne DSD 8 sub . Its magic. Its not subbish but rather Wooferish filling in,

 I have a dual 12 GR Research(Rythmik ) that is as musical as a sub should be, Its Danny Ritchies woofers that are paper vrs aluminum. I owned the 15 Rythmik and found it a but slower.
Sub woofers, Yes one per channel if you have the room, set up is the most important part, crossover and volume set so they blend in with your mains.I am not a bass freak but subs give you the complete sound your hearing for.