Hello! Well the TD15M has the smallest x-max and will suffer when used with high power in low frequencies… Like many other cloth-surround drivers including the JBL 2226. The M shines in the mid and midbass area where it gives you very high sound quality and high sensitivity.
If you want to compromise the sensitivity a little you can go with the TD15X and have much more x-max. But 8 cf3 is a lot. There are really many possibilities including the TD18h+ 8) But then you need a jigsaw…