Spent quite a bit of time yesterday and this morning listening and comparing the Minerva's to my Ie8's.
The main difference for me with the bass response on both of these iems is that although the ie8 goes a bit deeper it does add an overall bass depth to the music(hope that makes sense!), whereas the Mi-3 present the bass in a more subtle manner, it goes deep but doesn't add the overall bassy feel the ie8 do.
An example of this I found was on the track Barbariasm begins at home by The Smiths from the Meat is Murder album. There is quite a lengthy bass solo towards the end of the song, with the Mi-3 the bass is deep and textured but doesn't overpower the cymbal and drum beat going on in the background, the ie8 bass sounds great as well, deep but not as textured or subtle as the Mi-3. The bass from the ie8 on this track does overpower the rest of the track, not in a way that spoils the track as I do love the sound from the ie8 but it isn't as detailed or subtle as the Mi-3.
One thing I will say about the Minerva's is that they don't add any colour to the music or seem to have a special sound signature, I still feel they sound similar in detail to the um3x but with a tad more depth and soundstage and to my ears the mids feel a bit more forward than the um3x(in a good way).
The IE8 has a very warm sound and the bass is enhanced. You can get better deep bass response on the IE8 by setting the bass knob to max, which would make anything flat sound bass light in comparison. On the other hand, I do know what you mean by the bass differences between a balanced armature and dynamic driver. So, the question I would have about the Mi-3 is about bass roll off since you said it doesn't go as deep, or is it just because the IE8 bass is enhanced? Also, due to the human loudness curves you will perceive more deep bass from something with enhanced bass if the midrange volumes are set equal.