Awesome review as always Theremin! I do have some info on the modding side to add though. As nice as the boba housings are with GazzeW's U4 silent tactile & silent linear stems is about as bad as they are for modding. Really the top housings are the issue here as GazzeW made the tolerances so tight that very few stems from other switches will work with them without horrible binding (JWK/Durock to big, Gateron too big, Zealio/Tealio too big, modern Cherry to big, etc.). The bottom housings show much more modding potential, but much like the top housings not taking many other stems, the bottom housings are only compatible with top housings that do not have the 2 positioning posts that slip behind the leaf (only Outemu & Kaihl top housing as far as I'm aware). In fact the only stems I have on hand that fit were NOS vint Cherry black stems, Halo stems, & some of the Invyr PE V1 stems (tolerances too all over the place to recommend using these though).
Thankfully I was able to test out how these housings took to non silenced tactile & linear stems with Halo & vint black stems. Unfortunately though I have to say these are nothing special for modding, the leaf is so stiff you need springs weighted over 70g bottom out to get any non GazzeW/Outemu tactile stem to properly return & even the same goes for some of the linear stems I tried that were right on the cusp of the top housing's tolerances. With the vint black & Invyr PE stems that fit the tops I was able to bring the weighting all the way down to 55g bottom out springs, but then another issue cropped up. While these bottom housings are made of a softer nylon than normally used with switches it really doesn't make much of difference in feel when modding. The vint black stems in the boba housings felt almost identical to it being in it's Cherry housing. Reduced wobble was the only benefit to be found.
That said I did find that using NK/Kaihl top housings would open up the bottom housings to compatibility with many more stems, although again the feel is much the same as any nylon bottom housings. So after a good day of messing around with my batch of boba housings & U4 Boba silent tactile samples I have come to the conclusion that these are easily the best MX silent tactile switch out there right now (possibly the same for the linear variant, but beating MX Zilents smoothness is doubtful IMO), but DO NOT buy these for modding parts.
