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.