You can have any color shock spring you want as long as it’s red. 😉  Eibach springs are red and Eibach is just one town away from me so most of the shock springs I stock are red. Indianan is home to Hyperco, the maker of blue shock springs. I have some in stock and can order more. Normal size shock springs are $110.
My custom spring maker can make any size and/or color shock spring for $175.