Pricey but worth it - Radian Weapons Raptor LT SIG MPX Ambidextrous Charging Handle

I bought my MPX gently used for a very good price and have owned it for 5 years or so. Love the gun but felt the trigger and charging handle were the weak links. Decided to spend some cash and upgrade both (not that one should have to for the price of the gun). The original charging handle was better than the standard mil spec on an AR, but the raptor is still a huge improvement and worth the money if you plan on keeping the MPX forever. If you want a better trigger, look at the Timney PCC.