I notice that there are some modern cars still running a belt driven fan such as the 350z, Supra, Lexuses, and Skylines. Since they drain horsepower, what are the offsetting advantages to having one in place of an electric???

 

My first gen SC400 had an aux electric cooling fan which would run for several minutes after I shut the mill down.

Advantages are mechanical simplicity (and it gets to drive the water pump, too). It is not a source of much parasitic loss compared to, say, the A/C compressor.