I just noticed these on the Pelican site (pelican calls them Porsche Guide Rail Set Part#: 996-105-253-00-HBT)
They are less than half the price of the Porsche part. I am suspicious of cut rate parts, especially for a rather critical part like these pads, but could this be one of those cases where it is the same part from the same manufacturer but without the Porsche name?
By the way there is also a kit from HT with 4 pads to do both heads and it costs three times the price of the pads to do one head!
Just curious, I have to order pads soon.