A FLEXABLE CHASSIS IS JUST ANOTHER TUNING OPTION AS THE OTHER GUY SAID JUST FILE OUT A NOTCH ON THE SOLID TOP PLATE AND INSTALL THIER WONT BE ANY FLEX AT ALL. BUT FOR CARPET RACING YOU WANT A LIITLE GIVE IN THE CHASSIS CAUSE IT MAKES THE CAR A LITTLE MORE PREDICTABLE WHILE CORNERING MAINLY FROM THE CENTER OUT