IMO going with a black color will take away from the sight of a BBK. Even with bright colored writing the black caliper will just disappear into the darkness of the fender and wheel well. But then again he may want it to not stand out. But yellow with black writing with my word choice would be subtle enough to get the point across when parked in a sea of domestics. ****, there is alot that come to mind. "P&^^y" & "Magnet" then you got "Panty" & "Dropper" better yet "ICU" & "Hatin". All those 4 are not only true but again get the point across to any domestic you may pull up next to.
J/K though, but in all seriousness I would get something like pinstripped on for laughs at car meets and shows. This is also coming from the guy that has "Fuckin' Classey Ain't It?" on my front tower bar. Lol.