In a perfect world, Vorshlag would make Mazda Protege camber plates - they include a sealed bearing for the upper spring perch that separates the spring rotation from the upper spherical bearing. GC camber plates have a bearing too, but I don't think it is sealed. Just about every other one will have some sort of popping noise when you turn since the bottom of the spring rotates with the shock housing and the top perch is attached to the upper bearing. The spherical bearings used on the top are really designed to be loaded perpendicular to the shock shaft, so while they will take the loads (there's a standard derating for axial loads) they don't rotate well when axially loaded.
Another thing to keep in mind - camber plates LOWER the upper spring perch. If you could use them with stock springs (bad idea) they would jack up the front of the car. If you use them with sleeves, you end up giving up a fair amount of front-end wheel travel to get the ride height back to normal. If you want lowered and use the car on "normal" roads, expect to be bottoming the front suspension alot. To get the normal amount of travel back ("up" travel) the shock and spring combination must allow it - this usually means less "droop" when the suspension is unloaded, but the car will bottom less.
Personally I gave up trying to get camber plates to work. I couldn't afford putting together something that offered better handling, quiet turning, and good bottoming resistance without either making them myself or paying big money for someone like AWR or Tri-point to make them for me. Your circumstances may be different though, so good luck!
