do i need ballast resistor?

A ballast resistor and a fusible like do not have the same function.

A ballast resistor reduces the voltage going across it. For example, in the ignition system, it reduces the voltage from the main harness from 12v down to about 9v going to the coil.

A fusible link does not reduce voltage, it simply melts and severs the connection should the amperage in the system get too high. Its designed to keep you from burning up your car in a high amp situation, it melts so your wire harness doesn't.

If you have the stock ignition system, you need a ballast resistor. Some coils have an internal ballast, so if you really want to get rid of the external ballast resistor you can get one of those. Keep in mind you'll still have a ballast resistor, it just will be inside the coil instead of out on the firewall.