DIY Speaker question

I have build a pair of home audio speaker not long ago using Dynaudio component systems plus two 12" Dynaudio 30W100 subs I salvaged from an old DIY system.

However it appears that the 12" subs cannot sustain the bass produced by action movies and has blow out (the foam rings are torn). As a result, I am trying to replace them.

Now I am at a dilemma:
I don't want to spend over $800 on another pair of Dynaudio Subwoofers if it will not benefit. Yet, I don't want cheap quality parts that will interfere with my music.

I was told by many members here that for music, 12" subs will do more harm than good. Therefore, a potential solution would be to buy a decent, but not expensive pair of replacement subs and turn them on only for movies, NOT for music.

What's your guys take on that?

Thanks!!