One thing that was pointed out to me was that the Transport Cerbs have a larger range ( by like 100m), so it IS possible to kite your way out of their weapon range and pummel them with yours.
I don't think that even a higher armor upgrade would save the Raba though. I mean, it's double the DPS after all. Unless the difference was from a Uni 8 to a Cap 8 ( or even 6), then the armor would make a difference.
