18 Ray and Zurawski use the same electric carving knife that your grandma uses every Thanksgiving to shape the seat insert. When shaping your insert, begin by carving away the obvious overflow, then slowly remove foam until the driver is comfortable. Don’t forget to cut openings in the insert for belt pass-throughs. This is the part of the process where it pays to take your time. It’s always better to make many small cuts and slowly work your way to the desired fit than cut too much. You will probably need to fit the insert in the seat and have your driving make multiple fittings as you slowly carve away foam each time. Cut around the edges until the insert fits completely within the seat and your driver has sufficient arm and leg movement so that the insert doesn’t restrict their ability to drive the race car.