u/Disixivity

I have been in the hobby for 3 years now, and I wanted to make a DMR style of gun so I just picked up a Cyma M14 from Taiwangun (I am big on Vietnam-war style stuff and I also think it is a very appealing replica). What are some general pieces of advice when it comes to this replica, and what should I upgrade inside of it first, to get the best preformance? I have looked at some stuff online but I felt like I should ask for the opinion of people who have more experience with this specific replica, or DMRs in general.