FBO or MSD what do you use?

We are running the Hy-Fire Mallory box, this is our first encounter with after market ignitions. At the Fling, I didn't see anyone running a Mallory Setup and it kind of worries me. We have the hy-fire box and the matching distributor. I have heard good things about them and i couldnt beat the price. Someone had mentioned earlier that they are not water proof??? Should we mount our box in the cab under the dash ?