Yeah it's illegal to "alter the plate in any way". My dad cut about 1/8" - 1/4" off the top of my old plate on my s10 because he built a wooden ramp that rested on the bumper and the plate stuck up too far. I got pulled over for speeding and got a ticket for the cut plate (and not the speeding).
For years Texas allowed only a white plate with black letters or black plate with white letters. BORING! When Univ. of Texas folks starting putting little orange Longhorn decals on their plates - just decoration but not where they obscured anything, people got ticketed! Fortunately TX now has some decent looking plates though they're still in the dark ages requiring both a front and back plate.
I didn't think it would fly but I just hate the look of the Kansas plate. A black background with red or white letters would be perfect for my truck. Oh well I guess.
States could probably make some cash if they would let you choose your own colors. I know I would pay extra for it
I have painted over the colored letters on my CA plate before so it was white and pewter (to match my camaro). Got pulled over plenty of times and they never said anything. I think it was because the reflective part was un touhed and nothing looked to modded