Nissan needs to figure out what it wants to do with its aging Z car. Perhaps this new SEMA show special is a good place to start. Yes, say hello to the Nissan 370Z Project Clubsport 23. It’s a 400-horsepower potential answer to the question of “What’s next for the Z?” Gone is the 3.7-liter V-6 normally found under the hood of the 370Z. In its…