I can say that if my car in on Neutral it kind of behaves strange. As if was out of breath. I can aslo feel a kind of rattle sound from underneath. When the brake discs were replaced all has been cleaned properly and copper grease was applied. However, which EBC drilled discs I have a noise out of them is I am slowing down from a high speed.

This a tyre out off shape issue I had this with brand new tyres, 1 off the tyres had an egg shaped bump i a part off the tread.

When you had them balanced you should have watched the shape of the tyre on the machine, very hard to see on car.