i've just got a bora at the weekend and when the wheels spin in the snow it makes this grinding/ clicking noise which sounds strange, not like traction control on my old mk4 20vt, or the power cut tc style on my old ibiza 20vt. i had another bora 2.0v last year same spec as this one but it never made that noise.
i also noticed with this one, i turned into an icy road and it was understeering like mad so i counteracted with a tug of the handbrake and a simular noise came from the rear end - sort of high speed clicking. i guess it's all some form of traction control or the abs sensors not liking whats going on.
i used to be a gearbox mechanic by trade so will endevour to find out what it is and will let you know, it does sound nasty though!