There are a number of reviews you can look at on Amazon: Click here
A notable quote from a Jeeper:
"I purchased this product for faded gray trim on an '05 Wrangler. I am happy to say that back to black successfully restored the color of my fender flares to "like new" condition. Best of all, it stayed that way for several weeks, despite lots of bad weather.
The folks on here that complain of "streaking" or the results not lasting, must not be following the directions properly. The product must be MASSAGED WELL into the trim/moulding, allowed to dry, than buffed with a soft cloth or microfiber towel. If these simple directions are followed, the product does not streak when it gets wet, and the results LAST!
Simply wiping it on like Armor-All and letting it sit will not work properly.
I highly recommend this high quality product. Just make sure you follow the DIRECTIONS!!"
At under $7, it's probably worth a try. Looks like you just have to stick to the directions if you want results.