I replaced all the shocks on my 98 MkII at 98K, mainly as there were problems with uneven tyre wear. My friend who did the work said that when he checked them after removal, only one of the shocks was in need of replacing. The replacement shocks were KYB's. The ride is now marginally firmer which is not what I personally wanted. I'm not sure that new shocks will solve the 'jiggly' ride problem as this may be a 'feature' of the GS, others may be able to comment.