i dont know of any new cars that come with a fan that runs off of the engine...they are all electric. with something like my wifes 94 ram, yes...going from the clutch fan spinning on the water pump to the electric fans made a difference, but im about 99% sure that it comes with an electric fan.

as for the other items...

i believe that K&N claims 13hp from their full length intake...i think that superchips or someone makes a "Canned tune" in a hand tuner for the chargers, but im not sure what motor...and just changing the mufflers wont add any real power. now, if you went to a full exhaust system including headers, that would make a difference.