What pads do you have in?
I had the DS3000s and had exactly the same problem with the juddering that your describing,
I ended up putting a leading edge onto the pads (like the top ones in this pic)
Its a thing we do on the pads in the race car to give them more feel and a little less bite in the wet, Matt did mention that the grooves in the disks are at a very aggressive angle, since i have put the chamfer on, the brake wobble has completely gone!
If your running the DS3000 pads make sure you dont let them get glazed tho, they really need to be kept at a high temperature for them to work properly!
Dont let the wobble put you off though, there absolutely awesome brakes and the feel you get from them is mega! (for a survo'd system anyway)