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 went through  subs. Big ones, small ones, from Hsu, Infinity, DIY, Horn, Isobaric, compund, etc. .Found they all degraded the sound. I tried a cheap servo-sub, and loved it.
Its the only type sub I can live with.
I use a pair of $150 buck Yamaha servo-subs, with my small Proac monitors. Marchand passive 4th order xovers.
I may upgrade someday to some more expensive servo subs, but for the last several years, they have satisfied me quite well.
I added an 8 inch powered sub to my ADS 300s and it is wonderful
The ADS are good down to 100hz and the sub adds exactly what's missing. The 300s Mids and Highs are Hard to beat at any price range.
Casteeb, I have SF Venere 2.0 and needed a little more low end for certain types of music. I was pointed to the Sumiko s.5 because it matched the tonal qualities of the SFs. I have been impressed with how the sub is almost undetectable the way it just fills in the lower frequencies without sounding like an extra speaker. Plus it looks damn good. I have it attached via the speak-on cable to the b speaker outs. 
Room is 13.5x12.5 with 9 ft ceiling. 
Post removed 
I highly recommend you look at SVS brand subs. There aren’t a lot of reviews, they are very positive. I just added an SB1000, their smallest and least expensive model, to my small room, bookshelf speakers system, and I’m thrilled. Good luck!