Are the Bilsteins in Zinc only available for lifted applications or can we get them for a stock suspension on a 03' 2500HD 4x4. I'm not a big fan of the yellow.

Blue and yellow only. Can of black spray paint works great.

The 5100s (zinc) are probably not tuned to your specific application (they go only by length), so I wouldn't count on being as happy with them. I have them on my Jeep, and they're on the soft side..