I got a Glock 19 Gen 5 three years ago. I contacted Glock today to see if they do exchanges of non-MOS slides for MOS, which they said they do not. So, I have a few questions:

1) Are there any reputable companies that mill the slides in such a way that it would be like the MOS; that is, able to mount different RDS's with different plates instead being milled to specifically fit only one RDS?

2) Would that void the warranty with Glock?

3) If modifying the slide is ill advised, what are some some of the better aftermarket Glock slides?