Well, first those temps are not bad at all. In fact, when Cosworth built my last 2.0 they said they want to see the motor ideally running 209F for water and 209F for oil. That's an ideal they admit never really happens, in reality usually a few over or under. So, I would not say you have temp issues in current config.
For autocross I had the issue of running the car hard and then coming to stop in the grid and my SC 2007 would then spike instantly over 220F and more with all that heat to get rid of and the car not moving. So it now has the Singular louvers and other upgrades and now sitting in grid that temp spike is gone. Have not had issue with rain, when car driven in the rain you get a ton of it through the front grille, the only interesting change is that some drops of water coming through the grille now exiting through the louvers. We don't get snow here so I cannot comment much on that.