It depends upon the type of car. If it is cars like E Class, S Class, Jag; then it has to be sophisticated & subtle look. If you talk about CLS, SLK, or AMG versions of Merc, then sporty design wins.
In short, whatever maybe the shape, it should go with its engine & dynamics.
Modifying car say Swift to make it like sports car looks cheap & down-market. It becomes more like Bajaj Pulsar being modified to give look of CBR or Hayabusa....but you know the real story when the light turns green at signal
Company Made is the mantra....no personal mods.