Just wanted to give back and share with you my experience with the after market Roof Rails. I bought mine from firstouch4x4-au on eBay. This is the same seller as caticaauto. The communication with the seller was good. My rails are piano black and I got them for $200. Pretty good price and the quality of the rails seems very good, however all other parts lacked the same quality. My kit was also missing the F & G guides listed in the manual that I received. Turns out they are not necessary if you insert the roof mounts into the cover plates and mount them together. Incidentally the manual i received was the Range Rover manual. It took me over 2hrs to fit the rails. Everything was going quite well until it came time to attach the rail to the brackets. I needed to add a washer on the second - front side roof bolt to raise the mounting brackets enough for the rail holes to line up enough so I could screw them down.
Next were the plastic covers. The rear covers went in without much of a problem and cover the mount quite well. However the front plastic covers are loose and do not cover much of the mount on the inside of the rail. Does not look good but you have to look to notice. Since the front covers were a bit loose, I used some outdoor quality double sided tape to mount them in place. The seller promised to send replacement but I doubt they will be any better. Here are a few pictures of the rails and the gap, the front plastic cap leaves.
As you can see the front-inside plastic covers to not do a good job - but this is hard to see