I get a very rapid vibration when I apply the brakes. More so at speeds above 50

You can still get rotors that are not "flat" right out of the box. Have them machined and when reinstall your wheels they are torqued to proper spec instead of just using impact. Also, have the steering and suspension looked at for probs.

u have a worped rotors does have disc rotors front and rear you need to turn then on a lave