Quick FYI for everyone. If you purchase a new M&P, don't expect to install an Apex RAM. I just went to install a RAM on an M&P9 I got Monday (test fire date was 06/12), and discovered that S&W is using the VTAC sear housing in other models now. Apex said earlier this year the were developing a RAM for the VTAC, but it's not out yet. Not really even sure how it can be done with this sear housing.
You can visually check the frame for this new sear housing by looking for the lack of hole/plug for an internal lock.