I think because wheels are only 18s, the brakes and callipers look proportionate and not too small. So the painting works.
However, i'd go for this color scheme: black or anthracite rims = yellow or bronze calipers, silver rims - red callipers.
Although personally I'd paint them body color, black or silver (not to stand out).
'14 Black F11 530xd - NOW
'07 Silver E86 Z4 Coupe 3.0si - SOLD '16
'07 Blue E90 325i - SOLD '12
'06 Silver E90 320d - SOLD '10
'98 Blue E36 320i - SOLD '06