2 meter coax digital or toslink?

I know that coax is preferable, but I always understood that 1 meter is the optimal length and anything longer or shorter may affect timing. On the other hand, there should be no difference for optical cables. I'm placing one of my digital components a bit too far on the rack and need to purchase a 2 meter coax or get a toslink. I know that many people will debate whether there is any difference between the two, but I would like to hear some "scientific" proof of the sacrifices of going with a 2 meter coax.

Elbert