You can gain access to the front and rear baffles by following these steps: 1.) Wedge the top plate off. It's held in by spring tension and you just pry a bit on the left, then pry a bit on the right and it pops up. Be sure you don't mar the paint while prying. I used a kitchen spatula. 2) Pry off the right and left panels. Don't let them fall to the floor because it would mar the paint or possibly even crack in half. The panels are made of medium density fiberboard, like particle board. It's heavy and sturdy but brittle. 3) Untie the string on top of the speaker, and loosen the string. Don't remove it. 4) Roll the sock downward to expose the baffles.
I bought a 10" woofer for an M3si about 2 years ago but I may have been the last customer for that part. My link for Mirage parts doesn't work any more. At that time, they were owned by Klipsh but Mirage still had parts in Toronto. I had to call New Jersey; they ordered from Toronto; then New Jersey shipped it to me. Good luck.
All the best,
Jim L'Hommedieu