I've been renovating my grow cab, so i figured i'd post some pics.
here's how it was:
air went through the carbon filter-light-fan and then directly out of the cab. all the electrical stuff was in the same spot, under the flower chamber.
and now:
i redid how the chamber was sealed off, it's now sealed with reflective insulation and velcro. all the flowering electrical is above the chamber, with the fan and filter for my 150. and i hung a desk fan, as well. it's not quite done; i have some mylar emergency blankets on the way to line the cab. it's much more quiet, has more free space, requires less power for ventilation, and is much more light proof now.