The f40 box is the one found in the bravo 2.0 and Vauxhall signum/vectra. It has a maximum torque rating of 400nm.
The m32 box has a maximum torque rating of 320nm.
My engine comes with 320nm as standard, so I'd be amazed if fiat would put the m32 box in as it would be on the upper torque limit and most likely fail