Braded brake lines will not make the car stop better but will require less effort to achieve the same stopping power of rubber hoses. With less flex in the hose you will get better pedal feel, it won't feel spongy.
Firewall flex would be due to the leverage put on the master cylinder through the pedal as it is being depressed. If there is flex present it is due to a week firewall not the brake lines.
Firewall flex would be due to the leverage put on the master cylinder through the pedal as it is being depressed. If there is flex present it is due to a week firewall not the brake lines.