If I were still competing, the rules I run under wouldn't allow me to remove a front seat. (rear seat is fair game) But, the car is retired from competition, so I'm not worried about saving weight that much any more.
The utility of a big open cargo area is nice, though. It's sort of like driving a mini 2-door, 2-seat SUV. That gets 45-50 mpg. And handles like it's on rails. And has good AC.