Unlike some other filters, the KIWA standard filter modules are very tight, I have 6 Kc filters in my homebrew receivers and if you have a signal just out of the passband you do not hear it at all.
Very sharp just like an SDR.
No microphonics in mine, but I run mine off about 15 volts (rectified filament power) and 4.5 volts may be a poor choice.
But like mechanical filters (or even better) they are very sharp filters, so if you pick a narrow filter, it will be very narrow, maybe good for ssb and cw...
I think one of the reasons my homebrew receivers outperform almost everything else I ever tried is the filters.
I modified my Sony ICF-2010 by removing and discarding the original WIDE ceramic filter and trading places with the NARROW ceramic filter.
In place of the original NARROW filter, I installed a KIWA potted narrow filter which required tapping into the 4.5volt supply and using Velcro to attach it the speaker magnet.
Audio(with the KIWA) in the NARROW position was terrible, sock in mouth even on side band. Also the potted filter was VERY sensitive to vibration and microphonic. The top of the speaker location was far from the best spot, but, not much room inside the radio for an alternate location.
I can't speak to their other filters as I have not tried them.
My two zloty, Roland..................