Nissan Sport Wind Tunnel Tests 240z
 

https://www.nissansportmag.com/downloads/videoaudio.html

Not the best test, but it'll give you some ideas. One thing I didn't like is that they didn't take off each modification to test another. They sort of just piled stuff on without any thought it seemed. The magazine is carried at Boarder's if you want to read the article, it's not very well written and seems like it's missing a lot, but still worth a look. Surprisingly the Whaletail spoiler did give better aerodynamics, along with massive downforce.