I refinanced my car through rate genius and saved over $6k in interest. If you are considering using rate genius, some things you should now:
Rate Genius is a third party that uses their connections to find a bank/credit union that will refinance your car with a lower interest rate. Rate Genius does not refinance the car themselves.
When you refinance your loan, do not go with the higher term (60 months). My original loan had 46 months left on it and originally they tried to refinance me for 60 months, which would have resulted in me being upside down on my car loan. Choose your new terms as close to the original term as possible (my new term is 48 months) You can always ask your loan officer for a shorter term.
When you refinance, you don't have to pay a car note for a whole month! I refinanced at the end of September and my first payment due will be in November.