Internal upgrade Advice for King Arms S&W M&P15

[STORMZOMBIES]

Hi i run a King Arms S&W M&P15 MOE and im wondering what internal upgrades to make as i know how to strip the gun repair and fix etc as i practised on cheaper guns but i have no experience upgrading so i would like some advice on what sort of things i should up grade on this rifle thanks 

 

[Hangtight]

First upgrade you need to make is to your punctuation... Please?