If you want the gray to stand out more, you could always take some 1/8" or 1/4" wide automotive pin stripe, and outline the gray decals.
You could use black pin stripe or match the pin stripe color to a colored rail.
Have done this on sleds before, where I modified or removed some of the factory decals. Looks good. Open one of the jpeg pictures in "Paint", and zoom in and you can draw in a pin stripe, then zoom back out.