The idle up should help a little with lowering temps. (you can test this by raising your idle to 1000 or so)
The board has 2 purposes.
The first is a low idle cut-off so the AC doesn't drop the idle too low.
The second (which I found out by experimentation as I couldn't find documented anywhere) is an adjustment that uses the thermistor to prevent evaportator ice-ups. If the evaporator gets too cold, you want to turn the AC off.
If you're not icing up, the board really won't get you anything.
