If you can build a sonosub, you can build the GR Research DIY kits

The X-MTM has a relatively large foot-print and will probably fall right
into the wife disapproval catagory. Instead of the X-LS, please consider
the 'X-SLS'. It's a transmission line cabinet version of the X-LS, that plays
lower and has better WAF than a X-MTM.
If you must build bookshelf speakers and will probably expand to multiples
for HT use in the future, then the X-CS are a really nice choice.
Get the Encore tweeter, regardless of the X series you choose.
https://www.audiocircle.com/index.php?action=gallery;album=10071