I did it myself in a few hours. Bought a roll from bmwshadowline.com in matte black. The part under the mirror I just did as best I could. If you inspect underneath it there is still some silver trim exposed. But to the general observer at most angles, it looks perfect. Been on 8 months now and holding up great.
Eibach Pro kit|Bilstein Sport Shocks|M3 Edition Grilles|Painted Reflectors|Matte Black Vinyl Window Trim|CF Performance Spoiler|35% Tint|19" Satin Black Avant Garde M359|Lux H8 160|OEM Aero Lip|M3 Side Skirts|M3 Mirrors with Performance CF caps|LCI Tails|M-tech Rear|Duke Dynamics CF Performance Diffuser|Cyba 4.0 Black Chrome