2way with sub or 3way with woofer?

Hi friends,

I want to go with a mw16p+tw29r sealed 2 way, and I want to add some bass.

1st option The kairos 3way module featuring sb29nrx woofer per channel

2nd option powered subwoofer, mono peerless xls with passive radiator going really low and tight.
 
How low (f3, f6, f10) do you want the bass to go? How large is your listening room? How much max SPL do you think you need or want??? I have the SB29NRX75-6 in about 33 liters sealed with an Aperiodic vent and I am getting an in room f3 at 37 Hz. I also have the Satori MW16PNW-4 (4 Ohm white cone). I have tried it in 15 liters closed and 15 liters vented both. I am upgrading to a Wavecor WF223BD01 for the bass band from about 200 to 800 Hz because the Satori just couldn't handle all the power I wanted for higher SPLs. The SB29 does really good deeper bass but the mid and upper bass are less than ideal for my tastes. I now have a 4-way with sub. There are some successful designs out there that use the SB29 vented (I wanted to use mine closed box since I have a separate sub woofer and plate amp for everything below 40 Hz). The Satori MW16 and MR16 are both some of my favorite drivers; they just won't do LOUD like I need. My 2 cents worth; feel free to ask me more details either here or with a PM. There is another member here that is ordering some Peerless/Vifa/Tymphany NE265 4 Ohm 10 inch woofers wholesale. (If you are interested; PM me and I'll share more info about that.)

https://www.parts-express.com/pedocs/specs/264-1516--tymphany-ne265w-04-spec-sheet.pdf

(This is said to have much better mid and upper bass than the SB29 while also having good deep bass as well)
 
Yes, two subs are better than one even if NOT "stereo". Room modes are better handled with two. In my case; I have only one sub and it is only for 40 Hz and below BUT; I will have stereo woofers (eventually) above 40 Hz. The choices are easier if you don't care about bass below 40 Hz (I do care; I listen to large pipe organs often that do 16 Hz). If you do a closed box with "some" 12 inch woofers (ie SB34 or similar); in room bass (stereo) is usually plenty good enough to satisfy most listeners because even the low A on the standard 88 key piano at 27.5 Hz will be reproduced. In general, if you want this low with most 10 inch woofers; you usually need vented. Again, it depends on how low and loud you want or need (and, of course, room size and placement have a great deal to do with this).