I'm looking for someone who might have tried this StarTAC CCM Navigator Car Kit with the FM extension. I would like to have some feedback to know if it is good or not.

Also, I am looking for feedback on this one: http://www.sharperimage.com/us/en/catalog/productview.jhtml?sku=SI523NK2

The first one goes through the car stereo. I never tried it and I'm not sure if this really works. The second one has been recommended to me by several persons but it does not go through the car stereo.