vibrating front end.

[Gambit]

simple way to check if you need spigot rings

measure the centre bore of the alloy, basically the hole in the centre of the wheel

if its bigger than 57mm then you need spigot rings.

[GTI-BOY]

I have the exact same problem!  

I jacked up the car and spun the wheels round, looking in from the side I noticed the alloy move upwards then down on every revoloution, they are only new wheels and I know they are not damaged/buckled, when I took off the wheel and tried refitting, I noticed that the spigot was the wrong size, I had to move the wheel slightly to line up the holes with the hub.

Chk the same with your wheels