They are worth having for tarmac events but only in conjunction with a forward anti roll bar . This makes it difficult to fit as the only obvious way is a bodge onto the std tca ! if your pockets are deep enough to have proper GpA alloy hubs and the correct tca;s then its a different matter .On gravel cars most do away with anti roll bars , so if thats your thing go for it !
These comments are made " in my Experience " before any one starts shouting - i race with people who have tried every type of mod to make these work and im still quicker on a 4x4 roll bar .