As few and far between as the M46 cars are, if it were my car, I would paint it the original color....
It's only made one way when it's hatched.
Not to say that you shouldn't make it to your liking, but an M46 is a rare option. When it's closer to the fender tag, it makes the M46 option all the more impressive to those who value those little codes.
Black is nice but the M46 code cars have the black stripe on the bottom so would that black be flat/semigloss black? It either will look sort of stealthy or else it won't be noticed as it is down low, unlike a flat or semigloss black hood which is very visible.
I like white cars but the medium to darker colors tend to accentuate body lines better IMO. I guess white E-bodies, unless they have a black vinyl roof, remind me too much of the Vanishing Point Challenger, even a white Cuda, but I'm goofy like that.