First set of replacements disks were fitted under warranty by my local Subaru dealer after skimming did not solve the problem, so the replacements should be the genuine article. The odd thing is that the brakes are fine when you first set off from cold and the problem gets worse with distance travelled not the number of times you brake. I regularly use the M40 between my home and the A34 Oxford turn off (about an hour) and after an hours steady motorway driving (less than 10 braking events) the brake judder is very noticeable. Whereas local short distance journeys with many braking events do not produce the same juddering effect.