That's a Great user name! I'm very curious about the Sony IER sets. I've never had the opportunity to hear any of them and they get such stellar reviews. Maybe someday.
The Sony M9 is a warm neutral all BA set that has very good technicalities (soundstage/imaging/instrument separation/details). Considering it has BAs inside, the timbre is quite natural, not much BA timbre that may plague other pure BA types. It is quite hard to drive though.
The Sony Z1R is a V shaped set with superb bass and resolution. But some users (including myself) have bad fitting with it, so unfortunately, it doesn't work for me. Big pity, I like the sound a lot. So maybe best to audition a set first and see if it fits before springing a purchase.