In this case a 914 is close to the perfect car for autocross. They are super light, so they change direction like a fly. The mid engine layout means they have excellent balance. Autocross is a low speed event, so the lack of power isn't the penalty it would be on a larger circuit. With modern tires a 914 should do extremely well.

I keep reading stories if people going to track day on their liter bikes and getting outrun by the instructor riding a 250cc scooter.