Harnesses, 3 or 4 pt., 2 or 3 inches?

[joshua.hignight at baptistcollege.edu (Hignight, Joshua Adam )]

So, what works best in scrioccos? I'm guessing 4 pt., but I'm not sure what matters between 2 and 3" harnesses.

Reason I guess 4 pt. is attaching to the rear seatbelt mounting points. 
 
 
A few clues would help, thanks. Whenever I finally get my scirocco running again, I could use to get rid of the stock belt on the drivers side. 
 
Thanks!