I have this kit as well, using stock sized PFC rotors, no issues with the calipers or brackets at all. I’m on a quest for more initial bite but I believe is a matter of finding the right pads for my needs. Other than the delivery wait, there was no issues with my order, Slonik replied all my emails promptly, better than some dealers stateside.
Had the brakes since December ’17 and cosmetically there are no issues, paint has no fade, chips, blemishes.
Source: https://www.m3post.com/forums/showthread.php?t=1423661&page=5
Slon Workshop 