anybody ever use Carchex to find an extended warranty..they just gave me a fantastic quote on my RS6

full full coverage (only radio and nav excluded...i asked about turbos, transmission, suspension etc.) on a 77K car for 3 years/36K miles for $3300...ummm sold. Not sure of negatives?????...will look at it closer when i get the package and the actual provider but assuming its a leggit company i think i might be happy. Have an 18 month period to do payments, no interest...thoughts?? Carrier is "Peoples Vehicle Protection"