I fitted these to my dCi about one month ago and the sills are much cleaner! Easy fit - using original screws which secure the wheelarch liners. Don't forget the screw beneath (access from below). Check your local dealer for best price. Part No KE788-9U585 for front set. KE788-9U586 for rear. I only fitted the front set as the rear bumper usually stays quite clean.
Fitted a pair of front mud flaps about a month ago. They were easy to fit, only needed two screwdrivers, it's much easier to use a stumpy driver for the underneath screw.
I finished off by using silicone sealant to fill in the small gap between the plastic under guard and the new flaps. I then covered the white silicone (I didn't have clear) with ziebart which is a black undersealant, to blend in the small gap. Can I say that the flaps (mudgaurds) work a treat!
Can I report, that while I was looking underneath, the jacking points that hang down, just behind the front wheels, had their sealant removed, (scraped) showing just the paint. This has been done by the main dealers while servicing the car. (I've never used a jack on the car yet) This could be a starting point for rust! I gave these a good coating with Ziebart. So it's worth giving these a looking at the next time you look under your car.