This is my personal carry so I want it to be absolutely 100% reliable under any condition. I have used Next Generation Arms when they were in Toledo, OR. I love my AR that I bought from them. They have another guy down in Toledo that does the ceramic coating. STS Arms LLC. | Advanced Ceramic Performance Systems |. Question is: has anyone gotten their upper components on a XD/XD-m coated and what have you seen as the upside/downside?