I assume you are talking about the E90 and E91 BMWs (1999-2006 and 2007-on 3-series, bith beautiful cars.)
I always liked Delphin Grey. Was the color on my 1986 3-series. Whole different car.
The Deep Blue is always good. Black on the cars looks good, but only so much so. White does look good.
Red = No
If they made it is Green, that would be something!
SIlver = too bland, no.
Or, Custom. I have seen a Delphin Grey one with a Black hood, and the Black fading on the doors to the front.. There is a youtube video that has it it is called Drifting Porsches, Lamborghinis, BMWs, etc.
I have a White BMW 3-series (new) on my watch. Great car.