I thought it was pretty easy thanks to the advice on the forum. Took me about 5-10 minutes to do both. I drilled to Swamp's 5/32" as I also got my markers from JLeviSW. I still had a touch of cracking on one side, likely due to not drilling far enough as I didn't want to drill through. It is quite secure, though.
I'm very happy with the results. Chrome is the enemy.
2015 SO/SO MT M3 :: Exec : Lighting : Adaptive : HK : CF trim : Full leather : DAP : Black 19's : sunshade
Crystalline tint 40%/70% on windshield : M performance mirrors, spoiler, splitters : Status Gruppe CF lip : RKP diffuser : Fully dechromed
Bavsound Stage 1 : V1 Savvy hardwired : Self-coded