I purchased the APEX Duty / Carry AEK kit about a month ago. The installation was a pain in the ass because I did all the work on my kitchen table but the effort was well worth it. Keep in mind that you will not be able to install the Apex Ultimate Striker Block part of the kit if you do not have a bolted down vise or a SW MP Sight Mover. After you install the entire kit you will need a sight mover at the range so you can rezero your sights.
Before I installed the Apex kit the trigger on my MP9 was mushy and had a false reset. After the kit installation the trigger was smooth and the trigger reset was pronounced. The trigger reset was a 100% better but it’s not as defined as in my Sig 229. The greatest thing about installing the Apex kit was that my groups at 50 feet were considerably tighter. You can see the before and after results below.