If you are not a gun doc do not buy am sr25 plain and simple. They are all proprietary parts inside and nothing is standard and anything that is standard is mixed between L85 parts PSG1 length parts. And parts only echo 1 makes. Also echo 1 has no midcaps only high caps.
I have an A&K sr25k and 6 months and 800$ I'm parts finally shooting the way I want it to. If you want a carbine go M4 if you want a DMR get a high end M14 if you are dead set on an sr25 just think about after purchase cost is all I'm saying.
Also if you are looking on evoke then yes echo one is the most expensive but actually it goes echo1, A&K, Ares, G&P and G&P urx.