Growing up in the '70 & '80s, black rims just seem to me that the owner lost a hubcap or two and either didn't care, or was too cheap or lazy to replace the hubcaps.
Again - that is just my
opinion on black wheels.
Now, having said that, there are some really nice black wheels out there, and some actually do appeal to me... depending on what they're on.
As far as those Magnums go, I'm with the others - I think black chrome would look better than that finish shown in the pic you provided. Honestly though, black chrome can also look a lot like excessive brake dust and the owner is too lazy to clean the wheels.
Interestingly enough - I like that look on your car. Those Grand Marquis rims actually look really good blacked out, and right at home on your car. I wouldn't change a thing. ::thumb::