Like some of the others, I personally would not go for the under hood mural ... but to answer the question ... In my opinion, I think the blue snake & red eyes looks pretty cool ... or make it more of a ghost image as suggested.
The brown snake is technically closer to a 'real' or 'original' Cobra (oh no

... not that again ... just kidding

) it does not have as much impact as the body color snake.
Like the guys said, it's your car, so knock yourself out !
- Tim