there's plenty of old threads on this subject. It was being beat to death about a year ago. some are black and some are colored to match your paint. Personally, I like the black ones. they seem to disappear better IMHO.
I installed the MOPAR splash guards this weekend. Install wasn't too bad, but be prepared to remove the rear wheels unless you use a different method of fastening them. A rivot gun won't fit between the rear tire and the splash guard. I bought the splash guards on eBay for $40.50 per set.
Someone on C/T told me that you can get the rivot gun for plastic rivots at Harbor Freight. I ordered one on-line. It was about $20 shipped. This includes a number of plastic rivots. Turned out that I needed one of them because I broke one that came with the splash guards. They don't give you any extras.