I've seen the High Gloss Shadow Line on a Space Grey Coupe and it looked "wrong". It looks good on black though, and might look good on the very dark blue (Monaco). I didn't spec it on my car (Sparkling Graphite) because it's a fairly dark grey and I thought the chrome trim lifted it a bit, and looked good with the chrome grille and alloys.
I'm wondering what the M-Sport's going to look like, but for now I'm quite happy with my choice of 335d SE, which seemed to look "right" with the chrome trim.
2012 F10 520d M-Sport, Sport Auto, Imperial Blue, Black Dakota, Sun Prot Glass. V-spoke 281 Winter wheel package
Previous BMWs: 2009 E92 320d M-Sport, 2006 E92 335d SE, 2004 E60 530d ASE, 2000 E39 525d SE, 1997 E39 523i SE