Remember that motor controllers need to spaced out so their fans will work, and if you can, mount them so that metal shavings won't end up in them.
Neat electronics get ruined when they catch on fire.
EDIT: I just reread vhcook's post and he noted the vertical spacing. I looked it up
here and it is actually 2" for Victors. (I couldn't find anything on Jags better than "adequate air flow" but I imagine it's something similar. I believe since the jaguars vent air out of the sides you need to leave space between them as well, but that's not as important for Victors.)