Ive done the ash-tray bomb, first make sure your cable will reach, 2nd the ash trays are very weak and break easy!!!!!!! you only need to cut one side of the ashtray, drill a hole in the back of the tray (for plug) along with a 2" tall rectangle in the dash (behind ash-tray for wire to go up and down with the tray)
Take the comp box and put it next to the ashtray, then mark it where it will fit, cut it out and then velcro the box up. great bomb!!! WEll worth the effort
Ian