For interest, and it may help some one, I've had my arch guards fitted for a couple of weeks now, and thought I'f let you know my thoughts. They are very unobtrusive, you barely know they are there.
But they don't half stop a lot if road grime getting thrown down the side of the car! Very, very impressed:
Hopefullly there will be some rears to match in the near future.
If interested, check out Arch Guardian on Facebook.