That's one Hell of a shot!
I wouldn't touch it personally - the slightly low contrast and less than optimum sharpness all convey the feeling of movement and dust being thrown up. It's a great original shot and it would be very easy to spoil it.
It looks like this was scanned from a print with a textured surface - you can see the texture in the ears. If you
have to scan from prints, always get your prints done on plain glossy or matte paper - textured prints never scan well, although for optimum quality from film you should really be looking at getting a decent negative scanner unless you're going digital any time soon. Having said that, even if you go digital and have a large archive of negatives, the negative scanner would probably still be worthwhile.