I suggest GA Firing Line. I have seen several Glocks worked over by them and they are top notch. Very nice machine work, stippling and cerakote. They can do it all in one place and very fair pricing for the quality work they do.
Take it to Accurate Ordnance. They do wonders with Cerakote. They have done Glock and other polymers and my long range tactical rifle built by AO looks incredible.
www.accurateordnance.com
Apex carry or competition kit. RAM short reset helps with quicker shooting for competition but not really needed for a carry gun. If the first portion of the pull is gritty then just polish the trigger bar and drop in the Apex sear or kit for a great trigger.