I have Trijicon sights on all three of my MPs. Ammo is a bit harder right now because nobody has 9mm but I choose my ammo based on DocGKR's tried and truly effective ammo
list. It's a list of ammo that has been tested and meets the standards for federal law enforcement use.
For IWB holsters you may may want to look at a
Custom Carry Concepts Quick Cover or TAC-1. CCC uses fairy thin Kydex that allows for a bit more comfort than most and has a lower ride than Comp-Tac which is another great brand of holsters. For a concealable OWB you might want to look at a
Black Dog Concealment. For something a bit more upscale take a look at
TT-Gunleather.