Hi Martin,
Im running track spec D2 coilovers in my r33 gts-t, i've had them for almost a year now. I bought them from EVO-R and they come with a full warrenty...
in the begining i had a problem with my rears, due to factory fault. i went back and had them exchange for new items, since then i havnt had any problems at all with them.
I use my car mainly for street, i find that they are alittle on the bumpy side (thou i run them on mid/hard damper setup) But when i take the car to track it handles extremmely good. there was a huge overall improvement in the car
Hope that helps Michael