Andy,
I have had the back Whitelines on mine for quite a while now - worth fitting - the car is more tail happy...
There was a good guide on scabby-net a while ago and on the whiteline website it has guides to what difference it makes to the cars and what you should fit. For non-track use, they seemed to recommend the rears only, from all of my researcg. The fronts and anti-lift kit will add a bit more "liveliness" into your driving!!
Brian