I installed the ebay splash guards from hongkong this weekend. They fit perfectly, The only con that I found was they only come with 2 screws per flap. So if you want them to be more "sturdy" you will have to add some screws yourself.
Anyways I put them on with the 2 screws and they feel ok, You can bend them a bit with your hand but this is mostly because they are screwed into plastic.
For the front flaps you have to drill a hole into the metal part of the car that wraps inside the wheel well for the 1st screw and the 2nd screw just goes into the plastic. (I had to pre-drill a hole for the metal screw, It wouldn't screw in on its own, I used a small drill bit)
For the rear flaps you use an existing screw that matches up perfectly (this screw uses one of those weird " * " shaped bits). And the 2nd screw goes into the plastic.
So because of the screw that goes into the metal and the one that's being re-used in the body they are on there pretty good, but it might be a good idea to add one more screw, I'll wait and see how they hold out for now.
Please ignore the dent in the rocker, It makes me want to cry looking at it. That happened 3 days before I put the splash guards on =( . I got stuck behind 3 guys on a city road and the guy in front slammed his brakes so we all had to slam and I got close to the guy infront of me so I couldn't avoid the piece of garbage on the road that my wheel flung up in the air, it smashed into the rocker *cry*.