Before you have the wheels balanced I’d check that the wheels are turning true (no wobble). They may not have the top hats on the rotors seated correctly. The other thing to check is that Panteras use hub centric wheels. Depending on the top hats used the hub may not be mating to the wheel correctly. Also some kits come with a couple of speed nuts that go over the wheel studs to hold the top hat. These can misalign the wheel. I assume the vibration is not just under braking.
Hopefully you had a Pantera vendor install the brakes and you can just take the car back to them. On the other hand if it was a Pantera vendor they should have done a test drive before returning the car to you.
Mike
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